Cloud Storage FUSE CLI reference

This document describes the gcsfuse command options used to interact with Cloud Storage FUSE. If you're using the Cloud Storage FUSE CSI driver to mount your buckets to your local file system in Google Kubernetes Engine, see Mount options for the Cloud Storage FUSE CSI driver.

The Cloud Storage FUSE command line interface (CLI), or gcsfuse CLI, is used to mount Cloud Storage buckets as file systems on a local machine.

gcsfuse CLI command structure

The following example shows the structure of the gcsfuse command, including required commands and optional gcsfuse options.

gcsfuse GLOBAL_OPTIONS BUCKET_NAME MOUNT_POINT

Replace the following:

  • GLOBAL_OPTIONS are the gcsfuse options that control how the mount is set up and how Cloud Storage FUSE behaves.

  • BUCKET_NAME is the name of the bucket to mount. For example, my-mount-bucket. Optional. Exclude a bucket name from this command to perform dynamic mounting.

  • MOUNT_POINT is the local directory where the bucket will be mounted. For example, /path/to/mount/point.

gcsfuse CLI options

gcsfuse option Description Valid value Default value
Disables authentication for requests. This option should be set if you're using a custom endpoint that doesn't support authentication. This option should also be set if you're using Cloud Storage FUSE with public buckets. Boolean value: true, false. false
The application name of the mount. String value, for example: my-bucket-mount. ""
Specifies a project to use for billing when the mounted bucket is accessed. This option is often required when mounting a bucket enabled with Requester Pays. String value representing a project ID. ""

Enables the file cache and specifies the directory for storing file cache data.

 A path, for example: /tmp/gcsfuse-cache-path. An empty value indicates this option is disabled. This gcsfuse option is disabled by default. ""
Specifies the protocol used for communicating with the Cloud Storage backend. http1

Exports metrics to Cloud Monitoring with the specified interval.

 Integer representing a value in seconds, for example: 10 (10 seconds). 0 specifies no exporting. 0
Specifies the path to the configuration file you want to use to configure Cloud Storage FUSE behaviors. A path, for example: /etc/gcsfuse.yaml. ""
Specifies an alternative custom endpoint for fetching data. The custom endpoint must support the equivalent resources and operations as the Cloud Storage JSON endpoint, storage.UNIVERSE_DOMAIN_NAME:443. If a custom endpoint isn't specified, Cloud Storage FUSE uses the global Cloud Storage JSON API endpoint, storage.googleapis.com:443. If authentication isn't supported on the custom endpoint you specify, set the --anonymous-access gcsfuse option to true to bypass authentication. An endpoint, for example: storage.googleapis.com:443. ""
Enables FUSE-related debugging output. This option has been replaced by the --log-severity gcsfuse option. To enable debugging output, set the --log-severity gcsfuse option to trace, which includes trace, debug, info, warning, and error logs. Boolean value: true, false. false
Prints Cloud Storage request and timing information. This gcsfuse option has been replaced by the --log-severity gcsfuse option. To enable debugging output, set the --log-severity gcsfuse option to trace, which includes trace, debug, info, warning, and error logs. Boolean value: true, false. false
Exits the program when internal invariant violations are detected. Boolean value: true, false. false
Prints debug messages when a mutex is held too long. If this gcsfuse option is specified, the severity level of logs is automatically set to trace, which includes trace, debug, info, warning, and error logs. Boolean value: true, false. false
Permissions bits for directories, in octal. Integer between 000 and 777 (inclusive). 755
Specifies asynchronous prefetching of parts of a Cloud Storage object into an in-memory buffer, allowing subsequent reads to be served from the buffer instead of requiring network calls. Boolean value: true, false false
Creates a type cache entry with the type NonexistentType if a file isn't found in Cloud Storage. If the file gets created in Cloud Storage but the NonexistentType entry for the file is cached, then Cloud Storage FUSE cannot request that file until the NonexistentType entry is removed from the type cache. Boolean value: true, false. false
Controls the write path flow so that data is uploaded directly to Cloud Storage as its written instead of fully staging the write locally and uploading it upon close() or fsync(). For more information about streaming writes, see Cloud Storage FUSE semantics in the Cloud Storage FUSE GitHub documentation. Boolean value: true, false. true

Specifies the maximum size in MiB that the file cache can use and lets you limit the total capacity the file cache can use within its mounted directory.
  • Integer
  • -1: Specifies the use of the cache's entire available capacity in the directory you specify for cache-dir. This is the default only if cache-dir is passed.
  • 0: Disables the file cache.
 -1
Determines whether the full object should be downloaded asynchronously and stored in the Cloud Storage FUSE cache directory when the first read is completed from a non-zero offset. This gcsfuse option should be set to true if you plan to perform several random reads or partial reads. Boolean value: true, false. false
Specifies the size of each read request in MiB that each goroutine makes to Cloud Storage when downloading the object into the file cache. Integer 200

Accelerates reads of large files by using the file cache directory as a prefetch buffer using multiple workers to download multiple parts of a file in parallel.

Parallel downloads are automatically enabled when you enable file caching. To learn more about file caching, see File caching in Cloud Storage FUSE.

To learn more about parallel downloads and how to configure supporting properties, Parallel downloads.

 Boolean value: true, false. true
The maximum number of goroutines that can be spawned at any given time across all the download jobs of files.
  • Integer
  • -1: Specifies unlimited parallel downloads.
  • 0: Disables parallel downloads. Can only be used if --enable-parallel-downloads is not passed or is passed as false.
 Twice the number of CPU cores on your machine or 16, whichever is higher.
The number of concurrent download requests per file. Integer 16
Specifies permissions bits for files, in octal. Integer between 000 and 777 (inclusive). 644
Runs the gcsfuse command in the foreground. Boolean value: true, false. false
Specifies the Group Identifier (GID) owner of all inodes.
  • Integer representing a GID.
  • -1: The GID of the caller is used.
 -1
Displays help about Cloud Storage FUSE. None None
Displays the Cloud Storage FUSE version you have installed. None None
Specifies how long the Cloud Storage FUSE HTTP client can wait to get a response from the server before timing out. Duration, for example: 1h10m10s for 1 hour, 10 minutes, and 10 seconds. 0s specifies no timeout. 0s
Instructs Cloud Storage FUSE to ignore system interrupt signals, like SIGINT triggered by Control+C. This prevents signals from terminating in-flight operations. Boolean value: true, false. true
Implicitly includes folders and managed folders. See Files and directories in the Cloud Storage FUSE GitHub documentation for more information. Boolean value: true, false. false
Enables the list cache and defines the time to live (TTL) in seconds of cached list entries. The list cache is kept in memory in the page cache, which is controlled by the kernel based on available memory.
  • Integer representing seconds, for example: 10 (10 seconds).
  • 0: Disables list caching.
  • -1: Bypasses entry expiration and always returns the list response from the cache when it's available.
 0
Specifies an absolute path to the credential JSON key file for authenticating requests to Cloud Storage. By default, Cloud Storage FUSE uses Application Default Credentials to authenticate requests. A path, for example: /home/example_user/gcloud-key.json. When this option is not set, Application Default Credentials are used.
Specifies the bandwidth limit at which Cloud Storage FUSE can read data from Cloud Storage, measured over a 30-second window. Floating point number. -1 specifies no limit. -1
Specifies a limit for operations performed per second, measured over a 30-second window. Floating point number. -1 specifies no limit. -1
Specifies the file for storing logs that can be parsed by Fluentd. A path, for example: /tmp/user-example-bucket-gcsfuse-logs.txt. stdout when Cloud Storage FUSE is run in the foreground or syslog when Cloud Storage FUSE is run in the background
Specifies the format of the log file.
  • text
  • json
 json
The maximum number of rotated log files to retain, excluding the active file that logs are written to.
  • Integer
  • 0: Retains all rotated log files
 10
Specifies whether rotated log files are compressed using gzip. Boolean value: true, false. true
The maximum size in megabytes (MB) that log files can reach before being rotated. Integer. The minimum value is 1. 512

The severity level you want Cloud Storage FUSE to generate logs for. The severity levels are ordered from lowest severity to highest severity. For example, when you specify warning, Cloud Storage FUSE generates logs for warnings and errors. Generally, we recommend using the info severity level.
  • off: disables all logging.
  • error: contains messages about serious issues that prevent Cloud Storage FUSE from completing an operation, or indicate a failure such as mount failures, permission errors, and critical input/output (I/O) errors.
  • warning: contains messages indicating potential issues that aren't critical but can lead to issues if not addressed. Potential issues include non-fatal connection issues, deprecation warnings, resource contention that might cause slight performance degradation, and retries for transient failures. This severity level also includes information provided in the error severity level.
  • info: contains general logging information such as startup and shutdown messages, or information about successful mount operations, progress updates, and configuration settings. This severity level also includes information about the warning and error severity levels.
  • debug: contains logging information such as startup and shutdown messages, or information about successful mount operations, progress updates, and configuration settings. This severity level also includes the information provided in the info, warning, and error severity levels.
  • trace: contains granular details about each Cloud Storage FUSE operation and function call, outlining the gcsfuse interaction with the kernel FUSE driver and Cloud Storage. This severity level also includes the details provided in debug, info, warning, and error severity levels.
 info
Specifies the maximum number of TCP connections allowed per server. This becomes effective when --client-protocol is set to http1. Integer between 0 and 2147483647. 0 specifies no limit on TCP connections. 0
Specifies the maximum number of idle connections allowed per server. This becomes effective when --client-protocol is set to http1. Integer between 0 and 2147483647. 0 specifies no limit on idle connections. 0
Specifies the maximum number of times an operation is retried if the operation fails, preventing endless retry loops.
  • Integer representing the maximum number of retry attempts, for example: 10.
  • 0: Allows unlimited retry attempts.
 0
Specifies the maximum duration that Cloud Storage FUSE is allowed to sleep in a retry loop with exponential backoff. Once the backoff duration exceeds the specified maximum duration, the retry continues with the specified maximum duration. Duration, for example: 1h5m50s (1 hour, 5 minutes, and 50 seconds) or 60s (60 seconds). 30s

Defines the time to live (TTL) in seconds of negative stat cache entries, which store results for non-existent files in the cache.
  • Integer representing seconds, for example: 10 (10 seconds).
  • 0: Disables negative stat caching.
  • -1: Allows unlimited negative stat caching and disables a TTL expiration.
 5
Defines the time to live (TTL) in seconds of cached metadata entries.
  • Integer representing seconds, for example: 30 (30 seconds).
  • -1: Bypass TTL expiration and serve files from the cache whenever they're available.
  • 0: Use the most up-to-date file. Using this value issues a Get metadata call to make sure that the object generation for the file in the cache matches what's stored in Cloud Storage.
 60
Specifies additional system-specific mount options. Most generic mount options in FUSE such as suid are supported by Cloud Storage FUSE and can be passed along with the -o option. Mount options in FUSE, for example:
  • rw: Mount as read-write.
  • ro: Mount as read-only.
 ""
Mounts only a specific directory within a bucket. A path, for example: /etc/gcsfuse.yaml. ""
Applies a predefined, optimized set of Cloud Storage FUSE configurations for caching, threading, and buffer sizes to help you achieve high performance for a specific workload type, such as training, serving, and checkpointing. To learn more about each predefined configuration based on your workload type, see Profile-based configurations for AI/ML workloads.
  • A string, for example, "aiml-checkpointing".
  • "aiml-training": optimizes performance for high throughput reads of large datasets and prevents Cloud GPUs and Cloud TPU hardware from waiting for data.
  • aiml-checkpointing: optimizes performance for high throughput writes for large files by drastically reducing the time it takes to save multi-gigabyte checkpoints, minimizing training pauses.
  • aiml-serving: optimizes performance for serving workloads by streamlining data access and applying caching mechanisms.
 ""

Exposes Prometheus metrics endpoint on the specified port and /metrics path.

 Integer representing the port you want to specify. 0

Specifies the maximum number of blocks available for buffered reads across all file handles.
  • Integer
  • 0: disables buffered reads.
  • -1: sets the value to unlimited blocks.
 40
Allows the renaming of directories containing fewer descendants than the specified limit. Integer between 0 and 2147483647. 0
Specifies the multiplier for exponential backoff between consecutive retries. Floating-point number. 2
Specifies whether to reuse the token acquired from --token-url. Boolean value: true, false. true
Specifies the chunk size of the data to be downloaded from Cloud Storage, in megabytes (MB). Integer between 1 and 1024. 200
Specifies the number of entries that the stat cache can hold. This gcsfuse option has been replaced by the --stat-cache-max-size-mb gcsfuse option. Integer 4096
The maximum size memory that the stat cache can use, in MiB. The stat cache is always entirely kept in memory.
  • Integer. We recommend the following:
    • 32 if your workload involves up to 20,000 files.
    • If your workload is larger than 20,000 files, increase the size by values of 10 for every additional 6,000 files, where the stat cache uses an average of 1,500 MiB per file.
  • -1: Sets no limit, where the stat cache use as much memory as needed.
  • 0: Disables the stat cache.
 32
Specifies how long to cache StatObject results and inode attributes. This option has been replaced by the --metadata-cache-ttl-secs gcsfuse option. Duration, for example: 20s (20 seconds). 60s
Specifies a path to the temporary directory where writes are staged prior to being uploaded to Cloud Storage. A path, for example: /mnt/ssd/example-user-gcsfuse-temp-dir. /tmp
Specifies a URL for getting an access token when the --key-file is absent. A URL. ""
Specifies how long to cache the mapping between names and files or directories in directory inodes, in seconds. This gcsfuse option has been replaced by the --metadata-cache-ttl-secs gcsfuse option. Duration in seconds, for example: 20s (20 seconds). 60s
The maximum size in MiB per directory that the type cache can use. The type cache is always entirely kept in memory.
  • Integer. We recommend the following:
    • 4 if the maximum number of files within a single directory from the bucket you're mounting contains 20,000 files or less.
    • If the maximum number of files within a single directory that you're mounting contains more than 20,000 files, increase the value by 1 for every 5,000 files, which is an average of around 200 bytes per file.
  • -1: Specifies no limit and lets the type cache use as much memory as needed.
  • 0: Disables the type cache.
 4
Specifies the User Identifier (UID) owner of all inodes.
  • Integer representing a UID.
  • -1: The UID of the caller is used.
 -1

Specifies the maximum number of data chunks available for streaming writes across all files. Each file uses one 32 MiB data chunk by default.
  • Integer
  • 0: disables streaming writes.
  • -1: sets the value to unlimited chunks.
  • Default value for low-specification machines with limited resources: 4
  • Default value for high-specification machines with a large amount of resources: 1600

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