JP3970535B2 - Data duplication method for storage system and storage system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a storage device system for performing data duplication (data backup) between a primary control device connected to a processing device (host computer) and a secondary control device connected to the primary control device. About.
[0002]
[Prior art]
As a method of duplicating data between the primary and secondary control devices, the primary and secondary control devices are connected by an interface cable, and the write request received from the processing device by the primary control device is controlled by the secondary side. A method of duplicating data by issuing it to an apparatus is generally known.
[0003]
Further, a method of duplicating data in a system in which each of the primary and secondary systems includes a plurality of (M, N) control devices and a write request is issued from the processing device to the M primary control devices. Is also known. This method is disclosed in, for example, Japanese Patent Laid-Open No. 11-85408.
[0004]
When each of the primary and secondary systems has a plurality of (M, N) control devices, each primary control device gives the write time when the write request is issued to the write request received from the processing device (host). Then, a write request is issued to each secondary control device connected by the interface cable, and write data and write time are transmitted to the secondary control device. On the other hand, in the secondary side system, one of the plurality of secondary side control devices is set as the master control device, and the set master control device and the other secondary side control device are in a one-to-one relationship with each other by the data transfer path. It is connected. Then, the sub-side control device other than the master transmits information on the write time of the write data received from the primary side control device (write time from the host to the primary side control device) to the sub-side master control device via the data transfer path. Send. The master control device determines the guaranteed time with reference to the information on the write time received from all the sub-control devices (including the write time information of the master control device itself). Here, the guaranteed time is “All the secondary side control devices have received all the write data to which the past write time (write time from the host to the primary side) than the guaranteed time has been received by the secondary side control device. It is a time that can be guaranteed to be. That is, the determined guarantee time indicates that all write data related to all write requests issued from the processing device to each primary control device before the guarantee time have been received (duplicated) by the secondary control device. Guarantee. The master control device notifies the determined guarantee time to all the secondary control devices, and each secondary control device can confirm that the duplication of the write data having the write time before the guarantee time is guaranteed. The control device informed of the guarantee time can use the data received from the primary control device before the guarantee time, for example, when the primary data is destroyed due to some failure. .
[0005]
[Problems to be solved by the invention]
In the above method, in a system in which the primary and secondary systems include a plurality of control devices, it is necessary to determine the guaranteed time in order to guarantee data duplication and use the secondary data. And in order to determine the guaranteed time, each sub-side control device transmits information on the write time to the master control device between the sub-side master control device and each other sub-side control device, Since the guarantee time determined by the master control device is notified to each sub-control device, each sub-control device other than the master sub-control device needs to communicate twice.
[0006]
In the above method, processing and communication for guaranteeing data duplication is concentrated on the master control device. Therefore, particularly in a system having a large number of control devices, the communication performance in the master control device There existed a subject which processing performance fell.
[0007]
Further, in the above method, the master control device must have a function and a physical configuration capable of individually communicating with the other (N-1) secondary control devices, and in particular, control for configuring the secondary system. When the number of devices reaches a large number, it has been difficult for the master control device to have a function and a physical configuration for communicating with all the other secondary control devices.
[0008]
Further, in the above method, considering the case where a failure occurs in the master control device, the function as the master control device is considered by distributing the functions as the master control device to the secondary control device and providing redundancy. In addition, it is necessary to distribute the physical configuration to each sub-side control device, and it is considered that it is very difficult to realize such a configuration.
[0009]
An object of the present invention is to solve the above-described problem, and to reduce the number of times of communication between sub-side control devices, and to improve the efficiency of processing that guarantees duplication of write data. Another object of the present invention is to distribute processing to each sub-side control device without concentrating the processing for guaranteeing the duplication of write data on one sub-side control device.
Other objects of the present invention do not require a secondary master control device, and can be realized even when the number of control devices constituting the secondary system is large (not affected by the number of control devices constituting the secondary system). It is to provide a data duplication means.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a sub-system is constituted by one or more positive-side control devices constituting the main system. 2 In a storage system that backs up data to two or more secondary control devices, when a write request is made from the processing device to the primary control device, time information related to the write time is added to the write request data. Storing in the cache memory in the primary control device; sending the stored write data and the time information to the secondary control device; and writing data to the cache memory in the secondary control device. And storing the time information, and sending the time information stored in the cache memory in the sub-side control device to another sub-side control device through a communication path connecting the sub-side control devices to each other. Step, time information of the first secondary control device received from the first primary control device, and time sent from the second secondary control device The old time information is sent to the next secondary side control device through the communication path, and the old time information is cycled between the multiple secondary side control devices, Determining a data guarantee time for guaranteeing that the write data has been duplicated between the secondary control devices. Other implementation methods are described in detail in the embodiments of the invention.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic configuration diagram of a data duplex system according to an embodiment of the present invention.
The primary composite storage device system includes a plurality (M units, 1 to m) of primary control devices 210, 220, 230, and 240. Each positive-side control device is connected to the processing device 10. The secondary composite storage system is composed of a plurality (N units, 1 to n) of secondary control devices 310, 320, 330, and 340. An interface cable 40 is connected between the processing device and the primary control device, and between the primary control device and the secondary control device. Further, the sub-side control devices are connected in a ring shape by a communication cable 50 so that the sub-side control devices can communicate with each other. Here, the names of the interface cable 40 and the communication cable 50 are used for convenience, but both may be used as long as they can communicate information. Further, in order to improve reliability, redundant interface cables 40 and communication cables 50 may be used.
[0012]
When the processing device issues a write request, the primary control device that has received the write request writes the data included in the write request to the secondary control device connected to the primary control device via an interface cable. Issues a request to the secondary control unit. When the write request data is transferred from the primary control device to the secondary control device via the interface cable 40, the reception order of the write request data received by the secondary control device is such that the host issues a write request to the primary control device. The order in which they are issued is not necessarily the same and may differ. For this reason, the secondary control apparatus needs to rearrange them in the correct order (the order in which the write request is issued). In order to realize this, the primary control apparatus assigns sequential numbers in the order in which write requests are received from the host, and when transferring write request data to the secondary control apparatus, the sequential numbers are also sent together. To. By referring to this sequential number, the secondary control device can know the order in which the host issued the write request.
[0013]
In addition, as a communication means between the secondary side control devices in the secondary side composite storage device system, a means when a plurality of secondary side control devices are connected in a ring shape with a communication cable is described, but as other communication means, A means for the sub-side control device to communicate between the sub-side control devices using infrared or wireless communication means, a means for connecting the sub-side control device by bus connection and performing communication using the bus, etc. are also conceivable. . Whichever communication protocol (communication means) is used, this embodiment described below Or embodiment and In the same way (this example Or embodiment It is possible to perform data duplication processing (by communicating the same type of information).
[0014]
Next, the configuration of the control device will be described in detail.
[0015]
FIG. 14 shows a configuration diagram of the positive-side control device 210. Note that the control device in this embodiment has the same configuration as that of the control device 210 regardless of the primary side and the secondary side. The control device exchanges data and control information with the processing device 10, exchanges data and control information with the other control device 111 (delivery of data and control information between the primary and secondary control devices), and a secondary composite storage device system And a microcomputer-controlled channel adapter 112 that exchanges data and control information among a plurality of sub-side control devices. Further, the control device stores a microcomputer-controlled disk adapter 114 that transfers data to and from an external storage device 113 such as a disk drive, a non-volatile cache memory 115 for storing received data, and shared information of the control device. A shared memory 116, a channel adapter, a disk adapter, a nonvolatile cache memory, and a bus 119 for transferring data and control information between the shared memories in the control device. Here, when the device in FIG. 14 is a primary control device, the other control device 111 corresponds to a secondary control device, and data transfer and communication between control devices between the primary and secondary control devices are performed between the two primary and secondary control devices. Done. When the device in FIG. 14 is a secondary control device, the other control device may correspond to the secondary control device in the secondary composite storage device system in addition to the primary control device. The control device 210 and the external storage device 113 are combined to constitute a storage system. This storage system is an external storage device when viewed from the processing device 10. When the processing device is a mainframe computer, the external storage device is called a subsystem.
[0016]
FIG. 15 is a detailed configuration diagram of the channel adapter 112 shown in FIG. The channel adapter 112 includes a data receiving unit 211 that receives data from the processing device 10 and the other control device 111, a data transmission unit 212 that transmits data to the processing device 10 and the other control device 111, and executes the present invention. The program includes a nonvolatile memory 117 that is a storage part of a program including the above program and a microprocessor 118 that is a program execution part.
[0017]
Next, using FIG. 2 and FIG. 3, the operation of the primary control device when the host issues a write request, and the primary and secondary control device when issuing a write request from the primary control device to the secondary control device The operation of will be described.
[0018]
FIG. 2 shows processing when the write request from the processing device 10 is received in the primary control device 1 (210). When the data receiving unit 213 (data receiving unit 211 in FIG. 15) of the primary control device 1 (210) receives a write request from the processing device 10, it adds time information to the write data and makes the redundant primary side redundant. The data is stored in the non-volatile cache memories 212a and 212b (the non-volatile cache memory 115 in FIG. 14), and a write request completion report is sent to the processing apparatus 10. As the time information, when the processing device has a timer and issues a write request to which the time information obtained from the timer is issued, the time information given to the write request can be used. On the other hand, when the processing device does not have a timer, the time when the write request is received from the timers of the plurality of primary control devices is acquired, and the acquired time information is used. As described above, the control device stores the sequential numbers together in the order issued by the processing device, that is, the order in which the primary processing device accepts the write request.
[0019]
FIG. 3 shows processing when a write request is issued from the primary control apparatus 1 (210) to the secondary control apparatus 1 (310). The data transmission unit 214 (data transmission unit 212 in FIG. 15) of the primary control device 1 (210) issues a write request to the secondary control device 1 connected by the interface cable 40, and the primary nonvolatile cache memory The write data, time information, and sequential number stored in 212a are transferred. The data receiving unit 215 (data receiving unit 211 in FIG. 15) of the sub-side control device 1 (310) is the received write data and time information (the write time from the processing device to the primary side, which is described in “Time” All the information "is the write time from the processing device to the primary side), and the sequential number is stored in the secondary nonvolatile cache memory 312a (the nonvolatile cache memory 115 in FIG. 14). Similarly, when a write request is received from the processing device between the other primary control devices 2 to m and the secondary control devices 2 to n, a write request is similarly sent from the primary control device to the secondary control device. publish.
[0020]
FIG. 4 shows the structure of the write data management information table 700 provided on the secondary nonvolatile cache memory 312a (the nonvolatile cache memory 115 of FIG. 14) of the secondary controller 1 (310). The secondary side control device 1 manages the write data received from the primary side control device 1 (210) by the write data management information table 700 provided in the secondary side non-volatile cache memory 312a. The write data management information table includes a sequential number 701, write data time information 721, address information 711 of the secondary nonvolatile cache memory 312a (the nonvolatile cache memory 115 in FIG. 14) in which the write data is stored, Stored. The secondary control device 310 does not always receive the write data sent from the primary control device 210 in order from the oldest time information, and the write data may be temporarily lost. Therefore, the secondary side control device refers to the sequential number 701 stored in the write data management information table, checks whether or not this number is missing, and continuously receives this sequence number without missing. Find the latest light request. Then, the sub-side control device determines that the write data up to the time indicated by the time information included in this write request has been received. That is, the secondary control device 310 refers to the write data management information table 700, so that write data having time information before any time has been continuously received, and write data having time information after any time has been received. You can check if there is any missing data. In the example of the table 700, the sequential number 705 is missing, and the sequential number is No. It can be seen that the write data of 5 has not been received and all the write data before the time information 4 has been received by the secondary control device.
[0021]
Each secondary side control device of the secondary side composite storage system has this write data management information table, and manages the write data received by itself and its time information. In addition, in the case where a plurality of primary control devices are connected to one secondary control device, the secondary control device has a write data management information table for the number of connected primary control devices. .
[0022]
Next, a method for guaranteeing duplication of received write data through the explanation of the operation for determining the guarantee time and the operation for notifying the guarantee time when the secondary control device that received the write data from the primary side control device will be described below. explain.
First, information that is circulated between the secondary control devices in order to perform the guarantee time determination and guarantee time notification process will be described with reference to FIG. FIG. 16 shows information circulated between the secondary side control devices, and is stored in the secondary side non-volatile cache memory 312a in the control device. Details of each information and how it is used will be described later. Serial # 2001 is unique information of the control device for identifying the control device, and is stored in the secondary nonvolatile cache memory 312a and also in the shared memory 116 of each control device. There are two types of request type 2002: “request type 1 = guaranteed time determination” 2003 and “request type 2 = guaranteed time notification” 2004. The sub-control device that received the request type 2002 performs “guaranteed time determination processing”. This information is used to determine whether to perform “guarantee time notification processing”. The guaranteed time 2005 is a time for guaranteeing that all the write data having time information before that time has been received by the secondary control device. The provisional guarantee time 2006 is a provisional guarantee time until the formal guarantee time 2005 is determined in the guarantee time determination process (details will be described later), and this information is stored in the secondary non-volatile cache memory 312a. The
[0023]
(1) Processing for determining guaranteed time
A processing process in each sub-side control device when determining a guarantee time for guaranteeing duplication of the write data received from the primary side control device will be described below. This processing process will be described by taking the secondary composite storage system shown in FIG. 6 as an example. Here, the system of FIG. 6 as an example has n sub-side control devices (310, 310, 343) having data receiving units (313, 323, 333, 343) and data transmitting units (314, 324, 334, 344). 320, 330, 340) are connected in a ring shape by the communication cable 50. The data receiving units (313, 323, 333, 343) correspond to the data receiving unit 211 in FIG. 15, and the data transmitting units (314, 324, 334, 344) correspond to the data transmitting unit 212 in FIG. .
[0024]
The reference time will be described. The secondary side control device 1 (310) refers to the write data management information table 700 of the secondary side control device 1 in order to guarantee the duplication of the write data. The sequential control number is used to check whether the data arrives continuously from the side control device, and the time given to the continuously received write data is stored in the secondary side non-volatile cache memory 312a as the “reference time” . The reference time determined in this way has been received by the secondary control device for all write data transmitted from the primary control device connected to the secondary control device and having previous time information. It can be said that the time can be guaranteed. The write data management information table 700 is included in each sub-side control device, and the reference time is determined for each sub-side control device and stored in the sub-side non-volatile cache memory of each sub-side control device.
[0025]
The process for determining the guaranteed time will be specifically described below.
[0026]
First, the operation of the sub-control device that transmits information for determining the guaranteed time will be described first. The sub-side control device 1 (310) determines its own Serial # (information unique to each control device) stored in the shared memory 116, request type = guaranteed time from the sub-side control device communication transmission unit 314. (The transmission request type is set to a type called guarantee time determination) and the temporary guarantee time (reference time stored by itself) 2006 is transferred to the secondary control device 2 (320) of the connection destination (FIG. 6). Transmission from the data transmission unit 314 to the data reception unit 323). The request type stores information on what the sending side control device 1 (310) is transmitting for, and the receiving side control device 2 (320) refers to the request type. Thus, it is possible to determine what processing should be performed.
[0027]
Next, the operation of the sub-control device that sequentially receives information transmitted by the sub-control device will be described with reference to FIG. When the secondary control device 2 (320) receives the request type 1 = guaranteed time determination from the secondary control device 1 by the data receiving unit (323) (step 802), it is stored in the received Serial # and shared memory. It compares with its own Serial # and confirms whether or not the received Serial # 2001 is different from its own Serial # (step 803). If they are different, the secondary control device 2 (320) determines its own reference time (step 804) and compares it with the temporary guarantee time 2006 received from the previous secondary control device 1 (310) (step 805). As a result of the comparison, if the reference time of the sub-side control device 2 (320) is earlier than the received temporary guarantee time 2006, the secondary control device 2 (320) updates the temporary guarantee time 2006 with the reference time of itself (step 806). Then, in step 801, the secondary control device 2 is updated in step 806 together with Serial # 2001 and request type 1 = guarantee time determination 2003 of the secondary control device 1 (310) received from the secondary control device 1 (310). The provisional guarantee time is transmitted to the next secondary control device 3 (330) (step 807). Conversely, if the received temporary guarantee time 2006 is older as a result of the comparison in step 805, the received temporary guarantee time 2006 is not updated, and Serial # 2001, request type 1 = The temporary guarantee time received in step 802 together with the guarantee time determination 2003 is transmitted as it is to the secondary control device 3 (330) (step 807).
[0028]
The above processing is repeated between all the secondary control devices, and finally, in step 807, the data transmission unit (343) of the secondary control device n (340) to the data reception unit (314) of the secondary control device 1 (310), Temporary guarantee time 2006, secondary side control device 1 (310) Serial # 2001, request type 1 = guarantee time determination 2003 are transmitted. In step 802, the secondary side control device 1 (310) confirms that the serial # 2001 received from the secondary side control device n (340) is the same as its own serial number in step 803. Recognizing that the guaranteed time 2006 is determined by making a round of all the secondary side control devices, the temporary guaranteed time 2006 is determined as the guaranteed time 2005. Then, the sub control device 1 stores this guaranteed time in its own nonvolatile cache memory (312a).
[0029]
The guaranteed time 2005 determined in this way is a time at which it can be guaranteed that all the write data transmitted from all the primary side control devices having the previous time information has been received by the secondary side control device.
[0030]
Further, in the case where a plurality of primary control devices are connected to one sub control device, the reference time of each sub control device is determined as follows. The other guarantee time determination processes are performed in the same manner as described above. The secondary control device has the same number of write data management information tables 700 corresponding to the connected primary control devices, and each of the primary control devices can be referred to by referring to the write data management information table 700 corresponding to each primary control device. It is possible to confirm to what time the write data has not been lost from the side control device and have arrived continuously. If the time is defined as a temporary reference time, the secondary control device stores the temporary reference time having the oldest time from the temporary reference times corresponding to each primary control device as the reference time in the secondary nonvolatile cache memory. . The reference time determined in this way is all the write data having time information transmitted from the plurality of primary side control devices connected to the secondary side control device is the secondary side control device. It can be said that it is a time when it can be guaranteed that it has been received.
[0031]
(2) Processing to notify the guarantee time
The guarantee time determination process has been described above, and it has been explained that the guarantee time 2005 indicates that duplication of all write data having time information before the guarantee time is guaranteed. Since the guaranteed time 2005 is not known, it is impossible to determine to what time the duplication of the write data having the time information is guaranteed. By notifying all the sub-side control devices of the determined guarantee time 2005 and knowing to what time each of the sub-control devices can guarantee the duplication of the write data, each sub-control device Duplication of write data with time information can be guaranteed.
[0032]
First, the sub-control device 1 (310) that determines the guarantee time and stores the guarantee time in the non-volatile cache memory sets the request type 2002 among the information circulated between the sub-side control devices as “request type = guaranteed time notification”. "2004 (transmission request is set to the type of" guarantee time notification "), and the determined guarantee time 2005 and the request type (guaranteed time notification) updated together with its own Serial # 2001 are updated to the secondary control device 2 (320). ).
[0033]
Next, the operation of the sub-control apparatus that has received the cyclic information having the guarantee time notification as the request type will be described with reference to FIG. In step 902, the secondary control device 2 (320) that has received “request type = guarantee time notification” by the data receiving unit (323) determines whether the received Serial # 2001 is different from its own Serial #. (Step 903). If they are different, the received guarantee time 2005 is stored in its own non-volatile cache memory (step 904), and the guarantee time 2005 received in step 902 is changed to request type 2 = guarantee time notice 2004, secondary side control device 1 (310). Together with Serial # 2001 of the remote control device 3 (330).
[0034]
The above processing is repeated among all the secondary control devices along the communication cable 50 connected in a ring shape. Finally, in step 901, the data transmission unit (344) of the secondary control device n (340) sends the secondary control device 1 The guarantee time 2005, the serial number 2001 of the secondary side control device 310, and the request type = guarantee time notification 2004 are transmitted to the data receiving unit 313 of (310) (step 905). Then, the secondary control device 1 (310) receives Serial # from the secondary control device n (340) in step 902, and in step 903, the received Serial # 2001 is the same as its own Serial #. Upon confirmation, it is recognized that the guaranteed time 2005 has been notified to all the secondary control devices, assuming that the guaranteed time notification has made a round of the secondary control devices connected in a ring shape.
[0035]
As described in (1) and (2) above, by determining the guaranteed time 2005 and notifying all the secondary side control devices, each secondary side control device has the write data on its secondary side non-volatile cache memory before the guarantee time 2005. It is possible to determine whether the write data is later or later, and duplication of write data having time information before the guarantee time 2005 is guaranteed.
[0036]
(3) Processing to determine the guarantee time and notify the guarantee time together
Next, a processing process in each sub-side control device in the case where the notification of the guarantee time and the determination of the next guarantee time are performed simultaneously will be shown. By determining the next guaranteed time and notifying the guaranteed time together, the processing efficiency can be improved. Further, in the conventional method, in order to guarantee duplication of data, communication between the master controller and each secondary controller is performed between the communication for determining the guarantee time and the communication for notifying the guarantee time. This processing method requires one communication between each sub-side control device by performing communication for determining the guaranteed time and communicating for the guaranteed time together (simultaneously). Thus, it is possible to guarantee data duplication.
[0037]
First, the secondary side control device 1 (310) determines the temporary guarantee time 2006 received from the secondary side control device n (340) as the guarantee time 2005, stores it in its own non-volatile cache memory 312a, and sets the guarantee time 2005 to it. Request type 2 = guaranteed time notification 2004 is transferred to the secondary control apparatus 2 (320). At this time, the secondary control device 1 (310) further determines the temporary reference time 2006, which is its current reference time for determining the next guaranteed time, its own Serial # 2001, request type 1 = guaranteed time determination 2003. At the same time, the data is transmitted from the sub-control-device communication transmitter 314 to the sub-control device 2 (320) that is the connection destination. That is, the serial number, request type 1 (guaranteed time determination), temporary guarantee time, request type 2 (guaranteed time notification), and guaranteed time of the self-control device are transferred together to the next secondary control device.
[0038]
Next, the operation of the sub-control apparatus that has received the guarantee time notification and the guarantee time determination request as one process will be described with reference to FIG. Upon receiving the request type 1 = guaranteed time determination 2003 and the request type 2 = guaranteed time notification 2004 together with the data receiving unit (323) (step 1002), the sub-side control device 2 (320) receives the received Serial # and itself Are confirmed to be different from each other (step 1003), and the received guarantee time 2005 is stored in its own nonvolatile cache memory (step 1004). Further, the secondary control device 2 determines its own reference time and compares it with the temporary guarantee time 2006 received from the secondary control device 1 (310) (step 1005). As a result of the comparison (step 1006), if the reference time of the secondary control device 2 itself is earlier than the temporary guarantee time 2006, the temporary guarantee time 2006 is updated with its own reference time in step 1007, and the process proceeds to step 1001. . If it is not the past, the received temporary guarantee time is left as it is, and the temporary guarantee time is not updated, and the process proceeds to Step 1008. Then, in the next step 1008, the secondary side control device 1 (310) received from the secondary side control device 1 (310) Serial # 2001, request type 1 = guarantee time determination 2003 together with the temporary guarantee time and the secondary side control device 3 ( 330), request type 2 = guarantee time notification 2004 and guarantee time 2005 are also transmitted to the secondary control device 3 (330) at the next stage.
[0039]
The above processing is repeated between all the secondary control devices, and finally, in step 1002, from the data transmission unit (343) of the secondary control device n (340) to the data reception unit (314) of the secondary control device 1 (310). Serial # 2001, request type 1 = guaranteed time determination 2003, temporary guarantee time 2006, request type 2 = guaranteed time notification 2004, guarantee time 2005 are transmitted. The secondary control device 1 (310) receives Serial # 2001 from the secondary control device n (340) (step 1002), and confirms that the received Serial # is the same as its own Serial # 2001. (Step 1003), it is recognized that the guaranteed time 2005 has been notified to all the secondary control devices. Furthermore, it recognizes that the received temporary guarantee time 2006 has been determined by making a round of all the secondary side control devices, and determines the temporary guarantee time 2006 as the next guaranteed time.
[0040]
By performing the guarantee time determination process and the guarantee time notification process together as described above, the number of times of communication between the sub-side control devices required to guarantee the duplication of the write data is once. It becomes possible to suppress to.
[0041]
Next, a case will be described in which a plurality of (two in the example) processes for determining the guarantee time and notifying the guarantee time are executed in parallel between the secondary control devices connected in a ring shape. By executing a plurality of processes in parallel, it is possible to shorten the execution interval of the process that guarantees duplication of write data. FIG. 9 and FIG. 10 are diagrams for explaining this. FIG. 9 is a conceptual diagram in the case where two processes for performing the guarantee time determination and the guarantee time notification together are performed in parallel between the secondary control devices connected in a ring shape. FIG. 10 shows a comparative example for showing the superiority of the method shown in FIG. 9, and shows a conceptual diagram when only one guarantee time determination and guarantee time notification process is performed.
[0042]
In FIG. 9, information 1 (1101) that circulates between the sub-control devices includes information for performing the guarantee time determination and the guarantee time notification described in the process (3) together. Type 1 = guarantee time determination 2003, request type 2 = guarantee time notification 2004, guarantee time 2005, and provisional guarantee time 2006. Information 2 (1102) is also information for guarantee time determination and guarantee time notification (circular information is different from the information 1), which is circulated between the sub-control devices. In FIG. 9, the guarantee time is determined by circulating the information 1 (1101) and the information 2 (1102) in parallel between the sub-side control devices (310, 320, 330, 340) connected in a ring shape. And two guarantee time notification processes are performed in parallel. This is because two pieces of information circulate simultaneously, so that the interval at which the information circulates is shorter than in the case where one piece of information is circulated, so that the guarantee time is determined and the guarantee time is notified faster.
[0043]
In FIG. 10, since only one piece of information 1 is circulated between the secondary side control devices connected in a ring shape, the information is compared with the case where two pieces of information are circulated simultaneously as shown in FIG. The interval of circulation becomes longer and the determination of the guarantee time and the notification of the guarantee time are delayed.
[0044]
Now, in FIG. 9 and FIG. 10, the interval between the time when the information is cycled between the four sub-controllers connected in a ring shape and the duplication of the write data having the time information before the guaranteed time is guaranteed. Let T (1201).
[0045]
In this case, in the example shown in FIG. 10, the write data duplication guarantee process is guaranteed by repeating one information 1 cycle, so that the write data duplication guarantee process is performed at intervals T as shown in FIG. Are repeated (1201, 1202,...). In other words, the write data before the interval T from the current time is guaranteed to be duplicated.
[0046]
On the other hand, in the example shown in FIG. 9, two pieces of information 1 (1101) and information 2 (1102) are circulated in parallel at intervals of T / 2 between a plurality of secondary control devices connected in a ring shape. It will be. Then, after the information 1 makes a round between the secondary side control devices and guarantees the duplication of the write data having time information before the guarantee time, the information 2 makes a round between the secondary side control devices at intervals of T / 2. Therefore, the duplication of write data having time information before the guarantee time is guaranteed. That is, when the write data duplication guarantee processing is repeated for two pieces of information (information 1 and information 2), the write data duplication guarantee processing is repeated at an interval T / 2 as shown in FIG. (1301, 1302, 1303, 1304, ...). In other words, the write data before the interval T / 2 from the current time is guaranteed to be duplicated.
[0047]
In this way, compared to the case where only one process for performing the determination of the guarantee time and the notification of the guarantee time together is executed between the secondary control devices connected in a ring shape (in the case of FIG. 10), By executing a plurality of processes (in the case of two in FIG. 9) for simultaneously determining the guarantee time and notifying the guarantee time between the connected secondary side control devices, up to the most recent write data 2 The weight can be guaranteed.
[0048]
In the above description, an example has been taken in which two processes for performing the determination of the guarantee time and the notification of the guarantee time are executed in parallel between the secondary control devices connected in a ring shape. By executing three or four in parallel, it becomes possible to guarantee duplication of even the most recent write data. However, it should be noted here that information for simultaneously determining the guarantee time and notifying the guarantee time is a plurality of simultaneous communication over the communication cable that connects the sub-control devices in a ring shape. It is necessary to be able to do it. Even if the sub-controllers are logically linked in a ring, if the information for processing to determine the guarantee time and notify the guarantee time cannot be transferred simultaneously on the communication cable It is difficult to shorten the guarantee interval T. For example, when logical connection is carried out using a bus, there is no sub-control device where the load is concentrated, but since the bus can only perform one communication at the same time, the guarantee time is determined and the guarantee time is notified. It is not possible to send two processes that perform the above together in parallel.
[0049]
Also, the write data in the secondary nonvolatile cache memory that is guaranteed to be duplicated is allowed to be discarded from the secondary nonvolatile cache memory after being written to the external storage device 113. Therefore, if duplication of write data is guaranteed quickly, write data can be written to the external storage device quickly, and write data can be quickly discarded from the non-volatile cache memory. The operating performance can be improved. That is, by performing a plurality of guarantee time determination and guarantee time notification processes in parallel, the time required to guarantee data duplication can be shortened, so the usage rate of the secondary nonvolatile cache memory associated with the data duplication process Can be reduced, and in the unlikely event that a failure occurs in the secondary system, the amount of data lost (the amount of data for which duplexing cannot be guaranteed) can also be reduced.
[0050]
FIG. 13 is an explanatory diagram when one sub-side control device 4 (340) is added online to a sub-system composed of sub-side control devices (310, 320, 330) connected in a ring shape. First, apart from the existing communication path a (1401) (part indicated by a solid line), the communication path b (1402) after adding one secondary control device 4 (340) using the communication cable 50 in advance. ) (Part indicated by a broken line). Then, one of the sub-control device 1 (310) and the sub-control device 4 (340) selectively connected to the data transmission unit of the sub-control device 3 (330) by the communication cable 50 is selected. The function of transmitting the information by designating the secondary side control device is provided, and the information transmission destination of the secondary side control device 3 is changed from the secondary side control device 1 (310) to the secondary side control device 4 (340) by an instruction (command). To switch to. This makes it possible to add a secondary control device online.
[0051]
As described above, the storage system according to the embodiment of the present invention has the following structural features and functions.
[0052]
In the present embodiment, all the sub-side control devices (N units) are connected by a communication path such as a communication cable, and each sub-side control device communicates with the connection-destination control device. Is configured to be patrol. For this reason, each secondary control device determines the guaranteed time by circulating the time information given to the write data received from the primary control device among all the secondary control devices along the communication path. Then, it is possible to guarantee the duplication of data by circulating information about the determined guarantee time to all the secondary side control devices along the communication path. In addition, regarding the communication path for circulating information, in the embodiment, a communication cable connected in a ring shape is used. However, even when communication means such as infrared or wireless is used as the communication path, information is transferred between the sub-control devices. Any communication means that can be circulated in the network may be used. Alternatively, a communication means may be used in which the secondary control device is connected to a bus and information can be circulated by communication between the secondary control devices using the bus.
[0053]
In this storage system, processing and communication for guaranteeing data duplication is shared by each sub-side control device, and processing and communication is concentrated on one sub-side control device. Is preventing.
[0054]
Also, in this system, no matter how many sub-side control devices are provided, each sub-side control device has a function capable of communicating with two control devices, that is, an information communication source and a communication destination. good.
[0055]
Further, each sub-side control device simultaneously transmits and receives time information (time information for determining the next guaranteed time) and information related to the determined guaranteed time, thereby ensuring data duplication. The number of communications between the sub-side control devices can be reduced to one.
[0056]
Further, when adding one secondary control device c between two secondary control devices a and b connected via a communication path, the secondary control device c to be added is replaced by two secondary control devices a. , B to establish a communication path in advance and switch the communication destination of the secondary control device a from the secondary control device b to the secondary control device c (1403), enabling the addition of online control devices It is said.
[0057]
In addition, regarding the function of performing double data writing between a plurality of M-to-N primary / secondary control devices, in the conventional method, in order to guarantee data duplication, the master control device and each of the other sub-control devices. In the present embodiment, the guarantee time is determined and notified by one communication between the sub-control devices. Can be performed simultaneously, improving the efficiency of data duplication processing, and even when the number of primary and secondary control devices is large, the load is not concentrated on one secondary control device. This indicates that data can be duplicated.
[0058]
【The invention's effect】
All the sub-control devices are connected in a loop, and each sub-control device can determine the guaranteed time by circulating the time given to the data received from the primary control device through the loop communication path. Further, the guaranteed time can be notified by circulating the determined guaranteed time on the loop communication path. Further, it is possible to perform consistent asynchronous copy of data from a plurality of primary control devices to a plurality of secondary control devices through determination and notification of guarantee times.
[Brief description of the drawings]
FIG. 1 shows an outline of a data duplication system according to an embodiment of the present invention. It is a figure .
FIG. 2 shows a processing flow of the primary control device in response to a write request from the processing device. It is a figure .
FIG. 3 shows a flow of processing of the secondary control device in response to a write request from the primary control device. It is a figure .
FIG. 4 shows a configuration example of a write data management information table provided in the sub-control device. It is a figure .
FIG. 5 is a flowchart of guaranteed time determination processing in the sub-side control device. Is .
FIG. 6 shows a connection relationship of a plurality of sub-side control devices connected by communication cables according to the present embodiment. It is a figure .
FIG. 7 is a flowchart of a guarantee time notification process in the sub-control device. Is .
FIG. 8 is a flowchart of a process in which a guarantee time determination process and a guarantee time notification process are combined in the secondary control apparatus; Is .
FIG. 9 is an explanatory diagram when two processes are performed in parallel with a guarantee time determination process and a guarantee time notification process;
FIG. 10 is an explanatory diagram when one process is performed that combines the guarantee time determination process and the guarantee time notification process;
FIG. 11 shows a process execution interval when one process is performed that combines a guarantee time determination process and a guarantee time notification process. It is a figure .
FIG. 12 shows a process execution interval when two processes, which are a combination of a guarantee time determination process and a guarantee time notification process, are performed in parallel. It is a figure .
FIG. 13 is an explanatory diagram when adding a secondary control device to the secondary system;
FIG. 14 shows the structure of the control device. To complete Show It is a figure .
[Fig. 15] Channel adapter configuration To complete Show It is a figure .
[Figure 16] Guaranteed time of Indicates information used for decision processing and warranty time notification processing It is a figure .
[Explanation of symbols]
10 Processing device
210, 220, 230, 240 Positive side control device
310, 320, 330, 340 Sub-side control device
40 Interface cable
50 Communication cable
212a, 212b Positive side non-volatile cache memory
213 Positive write data transmitter
215 Secondary write data receiver
312a Secondary nonvolatile cache memory
700 Write data management information table
313, 323, 333, 343 Subordinate control unit communication receiving unit
314, 324, 334, 344 Inter-sub-controller communication transmitter
1201, 1202 Duplication guarantee processing execution interval T
1301, 1302, 1303, 1304 Duplication guarantee processing execution interval T / 2
1401 Communication channel a

Claims (23)

A data duplication method for a storage system that backs up data from one or more primary control devices constituting a primary system to two or more secondary control devices constituting a secondary system,
When there is a write request from the processing device to the primary control device, the step of giving time information related to the write time to the write request data and storing it in the cache memory in the primary control device;
Sending the stored write data and the time information to the secondary control device;
Storing the write data and the time information in a cache memory in the secondary control device;
Sending the time information stored in the cache memory in the secondary side control device to another secondary side control device through a communication path connecting the secondary side control devices to each other;
The time information of the first sub-side control device received from the first primary side control device is compared with the time information sent from the second sub-side control device, and the older time information is Through to the next secondary controller,
Determining a data guarantee time for ensuring that the write data is duplicated between the plurality of sub-side control devices by making a round of the old time information between the plurality of sub-side control devices; A method for duplicating data in a storage device system. The secondary control device notifying the data guarantee time to another secondary control device connected via the communication path;
The data duplication method for a storage system according to claim 1, further comprising a step of making the data guarantee time circulate in the communication path between the plurality of sub-side control devices.   The sub-side control device transmits the old time information and the data guarantee time together to another sub-side control device connected through the communication path, and makes a round, and the plurality of sub-side control devices 3. The data duplication method for a storage system according to claim 2, wherein the determination of the data guarantee time and the notification of the data guarantee time among a plurality of secondary side control devices are performed together.   4. The data in the storage device system according to claim 3, comprising a step in which the sub-side control device executes a plurality of determinations of the data guarantee time and a round of notification of the data guarantee time in parallel at arbitrary time intervals. Duplexing method. A method of duplicating the data from a plurality of primary control devices that receive data to be written by a processing device to a plurality of secondary control devices,
A first step in which the plurality of primary-side control devices receive data from the processing device; a first information regarding the time at which the plurality of primary-side control devices receive the data from the processing device; and the data. A second step of transmitting to the plurality of sub-side control devices; and a third step in which the plurality of sub-side control devices perform cyclic communication between the plurality of sub-side control devices on the second information relating to the first information. And a data duplexing method.   6. The data duplexing method according to claim 5, wherein the third step is executed on a physical communication path that connects the plurality of sub-side control devices in a ring shape.   In the third step, the second information transmitted by the first sub-control device is updated with reference to the first information by the second sub-control device that has received the first information. 6. The data duplication method according to claim 5, wherein:   When the first secondary-side control device that has transmitted the second information receives the second information by the cyclic communication, the plurality of secondary-side control devices receive the data from the received second information. 8. The data duplication method according to claim 7, wherein a time at which duplication of data is guaranteed is determined.   9. The data duplication method according to claim 8, further comprising a fourth step of notifying the plurality of sub-side control devices of the guaranteed time by the cyclic communication.   The data duplication method according to claim 9, wherein the third step and the fourth step are executed together.   The data duplication method according to claim 9, wherein the step obtained by combining the third step and the fourth step is executed a plurality of times on a physical communication path connecting the plurality of sub-side control devices in a ring shape. A data duplexing method in a storage system that backs up data from one or more primary control devices constituting a primary system to two or more secondary control devices constituting a secondary system,
Connecting the sub-control devices to each other by communication means;
Circulating and communicating data management information through the communication means between the sub-side control devices, and determining common management information regarding data;
A data duplication method in a storage device system comprising: A storage system having a plurality of primary control devices that receive data to be written by a processing device, and a plurality of secondary control devices that receive the data as duplex data,
A plurality of data receiving units in the plurality of primary control devices for receiving data from the processing device;
A plurality of data transmission units in the plurality of primary-side control devices that transmit the first information about the time at which the data is received from the processing device and the data to the plurality of secondary-side control devices;
A data transmission unit in the first sub-side control device that transmits the second information related to the first information from the first sub-side control device to the second sub-side control device;
Receiving the transmitted second information, a data receiving unit in the second sub-control device,
The plurality of secondary-side control devices are storage systems that form a cyclic communication path.   The storage system according to claim 13, wherein the cyclic communication path is a physically ring-shaped communication path. A data duplication method for a storage system that backs up data from one or more primary control devices constituting a primary system to two or more secondary control devices constituting a secondary system,
When there is a write request from the processing device to the primary control device, the step of giving time information related to the write time to the write request data and storing it in the cache memory in the primary control device;
Sending the stored write data and the time information to the secondary control device;
Storing the write data and the time information in a cache memory in the secondary control device;
Sending the time information stored in the cache memory in the secondary side control device to another secondary side control device through a communication path connecting the secondary side control devices to each other;
Comparing the time information of the first secondary control device received from the first primary control device with the time information sent from the second secondary control device;
Sending the older time information to the next secondary control device through the communication path;
Determining a data guarantee time for ensuring that the write data is duplicated between the plurality of sub-side control devices by making a round of the old time information between the sub-side control devices;
Notifying the data guarantee time to another sub-control device connected to the sub-control device via the communication path;
The sub-side control device executing the determination of the data guarantee time and the notification of the data guarantee time in parallel at an arbitrary time interval;
A method for duplicating data in a storage device system comprising:   16. The data duplication method for a storage system according to claim 15, further comprising the step of making a round of the data guarantee time on the communication path between the plurality of sub-side control devices.   The sub-side control device transmits the old time information and the data guarantee time together to another sub-side control device connected by the communication path, makes a round, and between the sub-side control devices. 17. The data duplication method for a storage system according to claim 16, wherein the determination of the data guarantee time and the notification of the data guarantee time between the secondary side control devices are performed together. A data duplexing method in a storage system that backs up data from one or more primary control devices constituting a primary system to two or more secondary control devices constituting a secondary system,
Connecting the sub-control devices to each other by communication means;
Circulating and communicating management information data in parallel through the communication means between the secondary control devices, and determining common management information related to the data;
A data duplication method in a storage device system comprising: A method of duplicating the data from a plurality of primary control devices that receive data to be written by a processing device to a plurality of secondary control devices,
A first step in which the plurality of primary control devices receive data from the processing device;
A second step in which the plurality of primary-side control devices transmit first information about the time when the data is received from the processing device and the data to the plurality of secondary-side control devices;
The third step of cyclically communicating the second information related to the first information between the first sub-side control device and the plurality of sub-side control devices, wherein the first sub-side control device A third step of determining a time for guaranteeing duplication of the data from the second information received from the plurality of sub-side control devices;
The fourth step of notifying the guaranteed time to the plurality of sub control devices by the cyclic communication by the first sub control device, wherein the third step and the fourth step are combined. The fourth step of performing,
A data duplexing method.   20. The data duplication method according to claim 19, wherein the third step is executed on a physical communication path that connects the plurality of sub-side control devices in a ring shape.   The data duplication method according to claim 19, wherein the step of combining the third step and the fourth step is executed a plurality of times on a physical communication path connecting the plurality of sub-side control devices in a ring shape. A processing device;
A plurality of primary control devices for receiving data to be written by the processing device;
A plurality of sub-side control devices that receive the data as duplex data from the plurality of primary side control devices;
A plurality of data receiving units in the plurality of primary control devices for receiving the data from the processing device;
A plurality of data transmission units in the plurality of primary-side control devices that transmit first information related to the time at which the data is received from the processing device to the plurality of secondary-side control devices;
A data transmission unit in the first sub-side control device that transmits the second information related to the first information from the first sub-side control device to the second sub-side control device;
Receiving the transmitted second information, a data receiving unit in the second sub-control device,
The plurality of secondary side control devices form a cyclic communication path,
Storage system the first secondary controller generates the second information, and transmits in parallel the second information.   The storage system according to claim 22, wherein the cyclic communication path is a physically ring-shaped communication path.

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