CN103617136B - SCSI drive side and I/O request control method - Google Patents

Abstract

The invention provides a SCSI drive side and a control method for I/O requests. The control method includes: obtaining the corresponding physical block addresses according to the logical block addresses in the received multiple I/O requests, wherein the multiple I/O requests are for data access to logical blocks in multiple logical spaces in the SAN storage system Request; according to the continuity of the physical block addresses, combine the I/O requests corresponding to the continuous physical block addresses; aggregate the combined I/O requests into one SCSI command and send it to the SAN storage system. Through the above method, the present invention can merge I/O requests distributed in different logical spaces, thereby increasing the probability of merging multiple I/O requests during data access, reducing the interaction of I/O requests on the transmission channel, and significantly improving Access performance of I/O requests.

Description

SCSI drive side and control method of I/O request

technical field

The invention relates to the technical field of data access and storage, in particular to a SCSI drive side and a control method for I/O requests.

Background technique

Currently, SAN (Storage Area Network, storage area network) storage systems generally include physical blocks (Physical Blocks, PB) provided by multiple disk devices, and these physical blocks are combined by RAID (Redundant Arrays of Inexpensive Disks, redundant array of disks) technology, etc. A storage resource pool is formed, and the storage resource pool is allocated into multiple logical spaces (Logical Unit Number, LUN), and each logical space includes one or more logical blocks (Logical Blocks, LB).

When accessing data in the logical space, the host generates one or more I/O requests according to access requirements, and sends them to the SCSI (Small Computer System Interface, small computer system interface) driver side. Then the SCSI drive side generates a drive command and sends the drive command to the SAN storage system, and the SAN storage system reads and writes data in the logical space according to the received drive command. In the prior art, in order to improve the access performance of the I/O request, the SCSI driver usually merges multiple I/O requests to reduce their queue occupation and interaction on the transmission channel. However, the existing technology can only combine multiple I/O requests distributed in the same logical space, and has no significant effect on improving the access performance of the I/O requests.

Contents of the invention

In view of this, the present invention provides a SCSI driver side and a method for controlling I/O requests, so as to significantly improve the access performance of I/O requests.

The first aspect provides an I/O request control method for data access to a SAN storage system. The control method includes: receiving multiple I/O requests, and determining the corresponding block address according to the logical block address in the I/O request Physical block address, where multiple I/O requests are requests for data access to logical blocks in multiple logical spaces; according to the continuity of physical block addresses, multiple I/O requests are merged; the merged I/O requests are merged /O requests are aggregated into one SCSI command and sent to the SAN storage system.

With reference to the implementation of the first aspect, in a first possible implementation, the step of determining the corresponding physical block address according to the logical block address in the I/O request includes: sending a query command to the SAN storage system, and receiving the SAN storage The mapping table of the logical block address and the physical block address fed back by the system; according to the mapping table, the physical block address corresponding to the logical block address in multiple I/O requests is queried.

With reference to the first possible implementation manner of the first aspect, in a second possible implementation manner, the logical block address and the physical block address have the same byte block size.

In combination with the implementation of the first aspect, in a third possible implementation, according to the continuity of physical block addresses, the step of merging multiple I/O requests includes: selecting continuous physical blocks in the physical block addresses obtained from the query block address, and merge the I/O requests corresponding to the continuous physical block addresses for the first time; select the discontinuous physical block addresses in the physical block addresses obtained from the query, and perform I/O requests corresponding to the discontinuous physical block addresses The requests are sorted; the sorted I/O requests are merged a second time with the I/O requests after the first merge.

In combination with the implementation of the first aspect, in a fourth possible implementation, before the step of merging multiple I/O requests includes: predefining a merging section; merging the multiple I/O requests The steps include: merging the I/O requests corresponding to the physical block addresses located in the same merging section to form the first I/O request; and merging the I/O requests corresponding to the physical block addresses outside the same merging section Requests are not coalesced to form a second I/O request.

In combination with the fourth possible implementation of the first aspect, in the fifth possible implementation, the merged I/O requests are aggregated into one SCSI command, and the step of sending it to the SAN storage system includes: The /O request and the second I/O request are aggregated into one SCSI command, and the SCSI command is sent to the SAN storage system.

The second aspect provides a SCSI driver side, including: a first receiving unit, configured to receive multiple I/O requests, and receive a corresponding physical block address determined by the SAN storage system according to the logical block address in the I/O request, The multiple I/O requests are requests for data access to logical blocks in multiple logical spaces in the SAN storage system; the first processing unit is configured to, according to the continuity of the addresses of the physical blocks received by the first receiving unit, perform multiple The combined I/O requests are combined, and the combined I/O requests are aggregated into one SCSI command; the first sending unit is used to send the SCSI command to the SAN storage system.

With reference to the implementation of the second aspect, in a first possible implementation, the first processing unit is configured to generate a query instruction according to the multiple I/O requests received by the first receiving unit, and control the first sending unit to send the query instruction Send to the SAN storage system, the first receiving unit receives the mapping table of the logical block address and the physical block address fed back by the SAN storage system, and the first processing unit queries the physical block address corresponding to the logical block address in multiple I/O requests according to the mapping table block address.

With reference to the first possible implementation manner of the second aspect, in a second possible implementation manner, the logical block address and the physical block address have the same byte block size.

In combination with the implementation of the second aspect, in a third possible implementation, the first processing unit is further configured to select continuous physical block addresses among the physical block addresses obtained from the query, and set the I/ The O request is combined for the first time, and the discontinuous physical block addresses in the physical block addresses obtained by the query are selected, and the I/O requests corresponding to the discontinuous physical block addresses are sorted, so that the sorted I/O requests Do a second merge with the I/O requests after the first merge.

In combination with the implementation manner of the second aspect, in a fourth possible implementation manner, the first processing unit is further configured to predefine a merged section, and perform an I/O request corresponding to a physical block address within the same merged section Merging is performed to form the first I/O request, and I/O requests corresponding to physical block addresses outside the same merged section are not merged to form the second I/O request.

With reference to the fourth possible implementation of the second aspect, in a fifth possible implementation, the first processing unit is further configured to aggregate the first I/O request and the second I/O request into one SCSI command, And control the first sending unit to send the SCSI command to the SAN storage system.

The beneficial effects of the present invention are: different from the situation of the prior art, the present invention obtains the physical block addresses corresponding to the logical block addresses of multiple I/O requests in the SAN storage system, and according to the continuity of the physical block addresses, sequentially The I/O requests corresponding to the physical block addresses are combined, so that the combination of I/O requests distributed in multiple logical spaces can be completed, the queue occupation and interaction of I/O requests on the transmission channel can be reduced, and the I/O request can be significantly improved. O requested access performance.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings. in:

FIG. 1 is a flowchart of a method for controlling an I/O request according to a first embodiment of the present invention;

Fig. 2 is a functional block diagram of a preferred embodiment of the SAN storage system of the present invention;

Fig. 3 is the functional block diagram of the control system of the I/O request of the first embodiment of the present invention;

FIG. 4 is a functional block diagram of an I/O request control system according to a fourth embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them.

The present invention provides an I/O request control method, please refer to the flow chart of the control method in the first embodiment of the present invention shown in FIG. 1 . The I/O request control method of this embodiment is used to perform data access to multiple logical spaces LUN0, LUN1, ..., LUNx in the storage resource pool 240 in the SAN storage system 210 shown in FIG. A plurality of logical blocks LBO, LB1, ... LBa, ..., LBn included in spaces LUN0, LUN1, ..., LUNx perform data access. The above data access to the logical spaces LUN0, LUN1, ..., LUNx, the final entity is to access the data stored in the physical blocks PB0, PB1, ..., PBn. It should be noted that the data access mentioned throughout the present invention refers to any operation that can be performed on stored data, such as reading, calling, and writing data.

As shown in FIG. 1, the I/O request control method disclosed in this embodiment includes:

Step S11: The SCSI driver side receives multiple I/O requests, and obtains corresponding physical block addresses from the SAN storage system according to the logical block addresses in the I/O requests, wherein the multiple I/O requests are for multiple logical spaces Logical block for data access requests.

Referring to FIG. 2 , when it is necessary to perform data access to logical blocks in different logical spaces, the application of the host will correspondingly generate multiple I/O requests and send them to the SCSI driver side. For example, when performing data access to the logical block LB2 of the logical space LUN0, the logical blocks LB7 and LB50 of the logical space LUN2, and the logical block LB2 of the logical space LUN9, the corresponding multiple I/O requests received by the SCSI drive side are IO -1 (LUN0, LBA2, LEN3), IO-2 (LUN2, LBA7, LEN1), IO-3 (LUN9, LBA2, LEN2), IO-4 (LUN2, LBA50, LEN2).

After the SCSI driver side receives and completes the above I/O request, it generates a query command accordingly and sends it to the SAN storage system. Wherein, the query command is a SCSI command, which is sent to the SAN storage system through the bus in the form of a byte stream. In this embodiment, the SCSI command is preferably used as CDB (Command Descriptor Blocks, command description block) as shown in Table 1 below. Correspondingly, the parameter format of this command is shown in Table 2 below:

Table 1

Table 2

After receiving the query instruction, the SAN storage system parses its specific parameters, and obtains the logical block addresses of the logical blocks that IO-1, IO-2, IO-3, and IO-4 need to access in the system and their corresponding physical The mapping relationship of the physical block address of the block is shown in Table 3 below:

I/O request physical block address IO-1 (LUN0, LBA2, LEN3) (PBA10, LEN3) IO-2 (LUN2, LBA7, LEN1) (PBA2, LEN1) IO-3 (LUN9, LBA2, LEN2) (PBA13, LEN2) IO-4 (LUN2, LBA50, LEN2) (PBA100, LEN0)

table 3

The SAN storage system sends the mapping relationship to the SCSI driver side, which is specifically expressed as a response to the SCSI commands shown in Table 1 above through the mapping described in Table 4 below.

Table 4

In this embodiment, the mapping relationship obtained by the SAN storage system is a one-to-one correspondence between the logical block addresses of the logical blocks to be accessed in the multiple I/O requests and the physical block addresses of the corresponding physical blocks. Further, in order to facilitate the search, the preferred SCSI driver side of this embodiment first displays the received mapping relationship in the form of a mapping table, and then queries the physical block corresponding to the received multiple I/O requests in the mapping table. piece.

In other embodiments, the SAN storage system can also obtain the mapping relationship between all logical block addresses and physical block addresses, and send it to the SCSI driver side, so that the SCSI driver side can search for the physical address corresponding to the logical block address to be accessed according to the mapping relationship. block address. Alternatively, the SAN storage system may directly feed back the physical block address corresponding to the logical block address to be accessed in the multiple I/O requests to the SCSI driver side.

It should be noted that the mapping relationship mentioned throughout the present invention is specifically expressed as a one-to-one correspondence between the logical block address (Logical Block Address, LBA) of the logical block and the physical block address (Physical Block Address, PBA) of the physical block, and When using the SCSI command shown in Table 1 above, the description of the logical block address of the logical block and the physical block address of the physical block adopts the same byte block (Block) size.

Step S12: The SCSI drive side merges the I/O requests corresponding to multiple physical block addresses according to the continuity of the physical block addresses.

Referring to Table 3 above, it can be seen that the physical addresses of the physical blocks corresponding to the logical blocks that need to be accessed by the acquired IO-1, IO-2, IO-3 and IO-4 are (PBA10, LEN3), (PBA2, LEN1), (PBA13 , LEN2), (PBA100, LEN2).

Then, select physical blocks with continuous addresses among the obtained four physical blocks. Based on the continuity algorithm in the prior art, LEN represents the length (length) of the physical block. It can be seen that among the four acquired physical blocks, the continuous physical block addresses are (PBA10, LEN3) and (PBA13, LEN2). The I/O requests corresponding to the continuous physical block addresses are merged for the first time, that is, IO-1 and IO-3 are merged, and the merged form is IO-1-3.

Select the discontinuous physical block addresses, that is, (PBA2, LEN1) and (PBA10, LEN3) and (PBA13, LEN2) are discontinuous. Sort the discontinuous physical block addresses, and then merge the I/O requests corresponding to the sorted physical block addresses with the I/O requests after the first merge, that is, IO-1-3 and IO- 2 are merged, and after the merger is IO-2-1-3.

Step S13: the SCSI driver side aggregates the merged I/O requests into one SCSI command and sends it to the SAN storage system.

The SCSI driver side sends the merged I/O request, that is, IO-2-1-3, to the SAN storage system. Among them, IO-2-1-3 is an aggregated I/O request with discontinuous addresses. Since it aggregates I/O requests in different logical spaces, it needs an aggregated SCSI command to send it to the SAN storage system. The aggregated SCSI command can be in the CDB format shown in Table 5 below:

table 5

After receiving the aggregated SCSI command, the SAN storage system obtains the combined I/O request through processing, and completes data access accordingly.

According to the specific operation of data access, the format of the access command to be constructed is different. For example, when writing data in the logical space, a Data-Out Buffer command format needs to be constructed; when reading data in the logical space, a Data-Out Buffer command format needs to be constructed. In Buffer command format. When using the above-mentioned read and write command formats to access data, it is also necessary to distinguish the read and write processes. Specifically, the following table 6 is used for the write process, and the following table 7 is used for the read process. Show. Wherein, the parameter formats of the above-mentioned Data-Out Buffer command format and Data-In Buffer command format are shown in Table 8 below.

Table 6

Table 7

Table 8

Based on the above, it can be known that this embodiment obtains the physical block addresses corresponding to the logical block addresses of multiple I/O requests in the SAN storage system, and merges the corresponding I/O requests according to the continuity of the physical block addresses, thereby completing The merging of multiple I/O requests distributed in multiple logical spaces reduces the queue occupation and interaction of I/O requests on the transmission channel, thereby significantly improving the access performance of I/O requests.

The present invention also provides the I/O request control method of the second embodiment, which is described in detail on the basis of the control method disclosed in the first embodiment. The difference between this embodiment and the first embodiment shown in Figure 1 is:

In step S12, multiple I/O requests that are not in the same merged section are not merged. In this embodiment, the merging section is to divide the logical blocks (LBAs) of multiple logical spaces in the SAN storage system, so as to avoid that the merging of each LBA cannot be significant even if the distance between the transmission channels is large. Reducing the queue occupancy of I/O requests on the transmission channel does not significantly improve the access performance of I/O requests.

For the division size of the byte blocks of the LBA in the merged section, those skilled in the art can set according to actual needs, for example, the predefined merged section divides the LBA into 30 byte blocks, then LBA50 and LBA2, LBA7, and LBA2 are not in one Merge segments, that is, IO-4 (LUN2, LBA50, LEN2) and the above three I/O requests, namely IO-1 (LUN0, LBA2, LEN3), IO-2 (LUN2, LBA7, LEN1) and IO -3 (LUN9, LBA2, LEN2), if it is not in a merged section, then IO-4 cannot be merged with IO-1, IO-2, and IO-3.

The I/O requests corresponding to the physical block addresses within the same merging section are combined to form the first I/O request, that is, IO-2-1-3. The I/O requests corresponding to the physical block addresses outside the same merged section are not merged to form the second I/O request, that is, IO-4 (LUN2, LBA50, LEN2).

In step S13, the SCSI driver aggregates the first I/O request and the second I/O request into one SCSI command, and sends the SCSI command to the SAN storage system. The SAN storage system parses the SCSI command to respond to the first I/O request and the second I/O request respectively.

This embodiment can operate on multiple I/O requests located in different merged sections, and aggregate the I/O requests that cannot be merged with the merged I/O requests separately and send them to the SAN storage system in the same SCSI command , so as to maximize the merging of multiple I/O requests distributed in multiple logical spaces, reduce the queue occupation and interaction on the transmission channel of I/O requests, and significantly improve the access performance of I/O requests.

It should be noted that the logical block, logical block address, corresponding physical block, physical block address, and corresponding specific values in the above table disclosed in this embodiment and the above-mentioned first embodiment are for illustration and example only. . In other embodiments, those skilled in the art can make other settings according to actual needs, as long as the one-to-one correspondence between the logical block addresses of multiple logical blocks and the physical block addresses of multiple physical blocks is satisfied.

The present invention also provides an IO request control system of the first embodiment, as shown in FIG. 3 , this embodiment is based on the SAN storage system 210 , the SCSI driver side 220 , and the application 230 shown in FIG. 2 . The SCSI drive side 220 disclosed in this embodiment includes a first receiving unit 221, a first processing unit 222, and a first sending unit 223, and the SAN storage system 210 includes a second receiving unit 211, a second processing unit 212, and a second sending unit 213.

The first receiving unit 221 is configured to receive multiple I/O requests formed by the application 230 , where the multiple I/O requests are requests for data access to multiple logical blocks in the SAN storage system 210 .

The first processing unit 222 is configured to generate query commands according to multiple I/O requests received by the first receiving unit 221 , and control the first sending unit 223 to send the query commands to the second receiving unit 211 of the SAN storage system 210 .

The second processing unit 212 is used to obtain the mapping relationship between the logical block address and the physical block address in the SAN storage system 210 according to the query command, and control the second sending unit 213 to send the mapping relationship to the first receiving unit 221 of the SCSI driver side 220 .

The first processing unit 222 is configured to combine I/O requests corresponding to multiple consecutive physical block addresses according to the continuity of the physical block addresses.

The first sending unit 223 is configured to send the combined I/O requests of the first processing unit 222 to the second receiving unit 211 of the SAN storage system 210 . The second processing unit 212 completes data access in the SAN storage system 210 according to the merged I/O request.

The present invention also provides the IO request control system of the second embodiment, which is described in detail on the basis of the first embodiment. The differences between this embodiment and the control system of the above-mentioned first embodiment are:

The multiple I/O requests received by the first receiving unit 221 cannot be directly combined, but need to be sorted first. Specifically, the first processing unit 222 is further configured to select continuous physical block addresses among the multiple physical block addresses, and combine the I/O requests corresponding to the continuous physical block addresses for the first time. At the same time, select the discontinuous physical block addresses in the physical block addresses, and sort the discontinuous physical block addresses, and perform the second I/O request corresponding to the sorted physical block addresses with the I/O request after the first merge. secondary merger.

The present invention also provides an IO request control system of a third embodiment, which is described in detail on the basis of the first embodiment shown in FIG. 3 . The differences between this embodiment and the control system of the above-mentioned first embodiment are:

The multiple I/O requests received by the first receiving unit 221 are located in different predefined merged sections, and the merged sections may be predefined by the first processing unit 222 .

The first processing unit 222 merges the I/O requests corresponding to the physical block addresses within the same merged section to form a first I/O request. At the same time, the I/O requests corresponding to the physical block addresses outside the same merged section are not merged to form the second I/O request. Further, the first processing unit 222 also aggregates the first I/O request and the second I/O request into one SCSI command, and controls the first sending unit 223 to send the SCSI command to the second receiver of the SAN storage system 210 unit 211, so that the second processing unit 212 parses the SCSI command, and completes data access in the SAN storage system 210 according to the first I/O request and the second I/O request obtained through the parsing.

The SAN storage system 210 and the SCSI drive side 220 in the above-mentioned several embodiments of the present invention correspond to the I/O request control methods based on the above-mentioned embodiments, so they can have the same technical effect. And it should be understood that the disclosed division of the description modules of the SAN storage system 210 and the SCSI driver side 220 is only a logical function division, and there may be other division methods during actual implementation, for example, multiple modules can be combined or integrated to another system, or some features may be ignored, or not implemented. In addition, the coupling or communication connection between the modules may be through some interfaces, or may be in electrical or other forms.

As components of the SAN storage system 210 and the SCSI drive side 220, the above-mentioned functional modules may or may not be physical boxes, may be located in one place, or may be distributed to multiple network units, and may be realized in the form of hardware , can also be implemented in the form of a software function box. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of the present invention.

The present invention also provides an IO request control system of the fourth embodiment, which is described in detail on the basis of the IO request control system disclosed in the first embodiment shown in FIG. 3 . As shown in FIG. 4 , the SCSI driver side 220 disclosed in this embodiment includes a first receiver 321, a first processor 322, and a first transmitter 323, and the SAN storage system 210 includes a second receiver 311, a second processing device 312 and a second transmitter 313.

The first receiver 321 is configured to receive multiple I/O requests formed by the application 230 , where the multiple I/O requests are requests for data access to multiple logical blocks in the SAN storage system 210 .

The first processor 322 is configured to generate query commands according to multiple I/O requests received by the first receiver 321 , and control the first sender 323 to send the query commands to the second receiver 311 of the SAN storage system 210 .

The second processor 312 is configured to obtain the mapping relationship between the logical block address and the physical block address in the SAN storage system 210 according to the query command, and control the second transmitter 313 to send the mapping relationship to the first receiver 321 of the SCSI driver side 220 .

The first processor 322 is configured to combine I/O requests corresponding to consecutive physical block addresses according to the continuity of the physical block addresses.

The first sender 323 is configured to send the combined I/O requests of the first processor 322 to the second receiver 311 of the SAN storage system 210 .

The second processor 312 completes the access to the data in the SAN storage system 210 according to the merged I/O request.

In summary, the present invention obtains the physical block addresses corresponding to the logical block addresses in the SAN storage system in multiple I/O requests, and merges the I/O requests corresponding to the continuous physical block addresses, thereby being able to complete The combination of I/O requests distributed in multiple logical spaces reduces the interaction on the transmission channel of I/O requests and significantly improves the access performance of I/O requests.

The above is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technologies fields, all of which are equally included in the scope of patent protection of the present invention.

Claims (8)

1. a control method of I/O request, for carrying out data access to SAN storage system, it is characterized in that, described control method comprises: Predefining the merged section, the merged section is to divide the logical blocks of multiple logical spaces in the SAN storage system; receiving multiple I/O requests, and determining the corresponding physical block addresses according to the logical block addresses in the I/O requests, wherein the multiple I/O requests are for data access to logical blocks in multiple logical spaces ask; Merge the multiple I/O requests according to the continuity of the physical block addresses, where the I/O requests corresponding to the physical block addresses located in the same merged section are merged, so that forming a first I/O request; not merging the I/O requests corresponding to the physical block addresses located outside the same merging section to form a second I/O request; Aggregate the merged I/O requests into one SCSI command and send it to the SAN storage system. 2. The control method according to claim 1, wherein the step of determining the corresponding physical block address according to the logical block address in the I/O request comprises: sending a query command to the SAN storage system, and receiving a mapping table of logical block addresses and physical block addresses fed back by the SAN storage system; According to the mapping table, the physical block addresses corresponding to the logical block addresses in the multiple I/O requests are obtained by querying. 3. The control method according to claim 2, wherein the logical block address and the physical block address have byte blocks of the same size. 4. The control method according to claim 1, wherein the step of merging the plurality of IO requests according to the continuity of the physical block addresses comprises: Selecting continuous physical block addresses in the physical block addresses obtained by querying, and merging the I/O requests corresponding to the continuous physical block addresses for the first time; Selecting discontinuous physical block addresses among the physical block addresses obtained through query, and sorting the I/O requests corresponding to the discontinuous physical block addresses; Merge the sorted I/O requests a second time with the I/O requests after the first merge. 5. A kind of SCSI drive side, it is characterized in that, described SCSI drive side comprises: The first processing unit is used to predefine the merged section, and the merged section is to divide logical blocks of multiple logical spaces in the SAN storage system; The first receiving unit is configured to receive multiple I/O requests, and receive corresponding physical block addresses determined by the SAN storage system according to the logical block addresses in the I/O requests, wherein the multiple I/O requests are A request for data access to logical blocks in multiple logical spaces in the SAN storage system; The first processing unit is further configured to merge the plurality of I/O requests according to the continuity of the physical block addresses received by the first receiving unit, and the requests located in the same merged section Merge the I/O requests corresponding to the physical block addresses to form the first I/O request; do not merge the I/O requests corresponding to the physical block addresses outside the same merged section, to form a second I/O request, and further aggregate the merged I/O requests into one SCSI command; A first sending unit, configured to send the SCSI command to the SAN storage system. 6. The SCSI drive side according to claim 5, wherein the first processing unit is configured to generate query instructions according to the plurality of I/O requests received by the first receiving unit, and control the The first sending unit sends the query instruction to the SAN storage system, the first receiving unit receives the mapping table of the logical block address and the physical block address fed back by the SAN storage system, and the first processing unit according to the The mapping table is queried to obtain the physical block addresses corresponding to the logical block addresses in the multiple I/O requests. 7. The SCSI drive side according to claim 6, wherein the logical block address and the physical block address have the same byte block size. 8. The SCSI drive side according to claim 5, wherein the first processing unit is further configured to select continuous physical block addresses in the physical block addresses obtained by querying, and place the continuous physical block addresses The I/O requests corresponding to the addresses are combined for the first time, and the discontinuous physical block addresses in the physical block addresses obtained by query are selected, and the I/O requests corresponding to the discontinuous physical block addresses are sorted, To perform a second merge of the sorted I/O requests with the first merged I/O requests.