Command Reference

Running juicefs by itself and it will print all available commands. In addition, you can add -h/--help flag after each command to get more information, e.g., juicefs mount -h.

NAME:
   juicefs - A POSIX file system built on object storage.

USAGE:
   juicefs [global options] command [command options] [arguments...]

VERSION:
   5.1.1 (2024-09-20 1faf43b)

COMMANDS:
   help, h  Shows a list of commands or help for one command
   ADMIN:
     auth     Authorize a volume
     destroy  Destroy an existing volume
     gc       Garbage collector of objects in data storage
     fsck     Check consistency of a volume
     dump     Dump metadata into a JSON file
     load     Load metadata from a previously dumped JSON file
     version  Show version
     quota    Manage directory quotas
     heal     Heal a replicated volume
   INSPECTOR:
     status         Show status of a volume
     stats          Show real time performance statistics of JuiceFS
     profile        Show profiling of operations completed in JuiceFS
     info           Show internal information of a path or inode
     summary        Show data and files distribution of a directory
     debug, doctor  Collect and display system static and runtime information
     lsof           List open files
   SERVICE:
     mount    Mount a volume
     umount   Unmount a volume
     gateway  Start an S3-compatible gateway
     webdav   Start a WebDAV server
   TOOL:
     bench, benchmark  Run benchmarks on a path
     objbench          Run benchmarks on an object storage
     warmup            Build cache for target directories/files
     clone, snapshot   Clone a file/directory without copying data
     rmr               Remove directories recursively
     sync              Sync between two storages
     import            Import existing files from object storage
     merge             merge files together without copying.
     grep              parallelized file pattern searcher
     compact           Trigger compaction of chunks

GLOBAL OPTIONS:
   --verbose, --debug, -v  enable debug log (default: false)
   --quiet, -q             show warning and errors only (default: false)
   --trace                 enable trace log (default: false)
   --no-agent              disable pprof (:6060) agent (default: false)
   --pyroscope value       pyroscope address
   --no-color              disable colors (default: false)
   --help, -h              show help
   --version, -V           print version only (default: false)

Global options

Items	Description
-v --verbose --debug	Enable debug logs.
-q --quiet	Show only warning and error logs.
--trace	Enable more detailed debug logs than the --debug option.
--no-agent	Disable pprof agent.
--pyroscope	Config Pyroscope address, e.g. http://localhost:4040.
--no-color	Disable log color.

Admin

juicefs auth

Authenticate the client against JuiceFS Console, and fetch or update configuration file for the JuiceFS Volume, and stored in $HOME/.juicefs/$VOL_NAME.conf. This command is useful in the following situations:

• juicefs mount may require interactive input, which is not convenient for automation. Run juicefs auth in advance to authenticate and fetch the client config file, see Automation for more.
• If object storage bucket (or its access key, secret key) changed, juicefs auth is needed again to update the relevant information. For example, if object storage is migrated to another region, or switched to a different service provider, client config needs to be updated as well.
• ​On-prem When Metadata node IP changes, run juicefs auth again to reauthenticate and fetch the latest config. Most migration are executed without downtime, so you only need to update the config file, rather than restart the whole mount point (consult Juicedata engineer for specifics).
• For CSI Driver, if Metadata node IP, object storage, or on-prem Web Console address changes, you must update the volume credentials to trigger an auto update, CSI Controller runs juicefs auth to refresh the client config cache.

Synopsis

juicefs auth NAME [options]

juicefs auth myjfs --token xxx --access-key xxx --secret-key xxx

Options

Items	Description
NAME	Name of your file system.
--token=TOKEN	Token of your file system, obtain in JuiceFS Web Console.
--bucket=BUCKET	When a file system is first created, object storage bucket is already specified in the web console. When in need, client can override this setting by specifying this option, in order to for example, connect to object storage in special network environments. Same as the file system bucket setting in the web console, you can either specify the bare bucket name string, or the full endpoint starting with https:// or http://. These two method have different implications: If a bare bucket name is specified, client will automatically conduct a network test to choose between internal/external endpoints (if service provider supports), for example, when using OSS beijing region, passing --bucket=test causes client to automatically choose between https://oss-cn-beijing-internal.aliyuncs.com and https://oss-cn-beijing.aliyuncs.com, according to the network test result. Explicitly specifying --bucket=https://oss-cn-beijing-internal.aliyuncs.com, then client will respect this setting, without trying to deduce the full endpoint by itself. Usually, object storage service address resolves to multiple IPs, JuiceFS client randomly picks an available IP for each request for proper load balancing, this behavior is defined in JuiceFS Community Edition source code, which is also used in our Enterprise Edition.
--access-key=ACCESSKEY	Object storage access key, see How to get AK/SK. An interactive prompt will occur to collect this info if missing in the command line options. Leave empty if you have configured host to access object storage without credentials.
--secret-key=SECRETKEY	Object storage secret key, see How to get AK/SK. An interactive prompt will occur to collect this info if missing in the command line options. Leave empty if host have been configured to access object storage without credentials.
--session-token=SESSIONTOKEN	Optionally provide object storage session token.
--shards=0	Same as the Community Edition's --shards option. JuiceFS Enterprise Edition volumes are usually paired with scalable object storage services, and do not easily reach the single bucket performance (or capacity) limit. Hence, this option is provided to maintain compatibility, and should not be your first option because multi-bucket increases complexity.
--storage-class=value	Storage class for the destination storage, if supported. Read relevant docs for more, e.g. S3.
--bucket2=BUCKET2	Optionally provide the name or endpoint for the secondary bucket For Data replication, same format and caveats as --bucket.
--access-key2=ACCESSKEY2	When data replication is enabled, use this parameter to specify the access key for the secondary bucket. Learn more at Cross-region data replication.
--secret-key2=SECRETKEY2	When data replication is enabled, use this parameter to specify the secret key for the secondary bucket. Learn more at Cross-region data replication.
--session-token2=SESSION_TOKEN2	the session token to access the bucket (optional)
--shards2=0	When data replication is enabled, --shards2 must equal --shards.
--passphrase=PASSPHRASE	Passphrase for encrypted key, see Data Encryption for more.
--encrypt-keys	Encrypt the object access and secret keys locally or not (default: false).
--subdir=SUBDIR	Specify a sub-directory for mount, you can also create ACL to restrict client access to specific sub-directories, learn more at Client Access Control
--conf-dir=CONFDIR	Directory to store configuration files, default to ~/.juicefs)
--no-update	Client will by default obtain latest config from JuiceFS Web Console, set to true to disable this behavior, and then client will no longer talk to JuiceFS Console when mounting.

juicefs gc

Detect leaked objects, and delete them. Whenever object storage usage far exceeds file system size, and has been confirmed that it is not caused by trash retention or intensive overwrites, then there's possible object storage leaks, run this command to scan for leaks and delete them.

The most common cause is object storage service outage, many delete requests (invoked by trash expiration) could fail repeatedly, when this happens, in order to reduce load, the Metadata service discard the related metadata after a certain amount of DELETE failures, and just stop retrying. After object storage service goes back online, the discarded blocks will not be deleted since the corresponding metadata is already gone, thus becoming leaks.

Synopsis

juicefs gc [command options] VOLUME-NAME

# Check and print results, but don't actually delete anything
juicefs gc $VOL_NAME

# Delete leaked objects
juicefs gc $VOL_NAME --delete

Options

Items	Description
--delete	delete leaked objects (default: false)
--threads=10, -p 10	Number of concurrent threads, default to 10.

juicefs fsck

This command checks the file system's consistency. If any files have missing object storage blocks, use this command to find them.

Synopsis

juicefs fsck [command options] VOLUME-NAME

juicefs fsck $VOL_NAME

Options

Items	Description
--threads=10, -p 10	Number of concurrent threads, default to 10.
--repair	Fix the hash prefix of objects. JuiceFS Enterprise Edition automatically adds a hash prefix (slice ID mod 256, same as Community Edition's --hash-prefix) to all object storage blocks. This distributes data blocks evenly across actual object storage regions, offering more consistent performance. If a JuiceFS volume did not use this naming pattern (for example, importing a JuiceFS CE volume which disabled --hash-prefix), use this option to repair it.

juicefs dump

Dump metadata into a JSON file. Different from JuiceFS CE, JuiceFS EE require no manual metadata dump in order to make a backup, it's already handled by our engineers in the server end. Thus, this command is used mainly for debugging, or migration between CE and EE.

Synopsis

juicefs dump [command options] PATH JSON-PATH

# Export metadata to meta-dump.json
juicefs dump /jfs meta-dump.json

# Export metadata for only one subdirectory of the file system
juicefs dump /jfs/subdir meta-dump.json

Options

Items	Description
PATH	Mount point path.
JSON-PATH	Export file path. If the filename ends with .gz, it will be automatically compressed.
--gzip	Compress with gzip.

juicefs load

Load metadata into an empty file system, often used for migrations between JuiceFS CE and EE.

Synopsis

juicefs load [command options] PATH [FILE]

# Import the metadata backup file into the file system
juicefs load /mnt/jfs meta-dump.json.gz

juicefs version

Show the JuiceFS version information. The update details of each version can be viewed on the "Release Notes".

Synopsis

juicefs version [options]

# Upgrade client version and seamless restart
juicefs version -u -r

# When a new major version is released, there might be compatibility issues,
# use the following variable to rollback, e.g. downgrade from 5.2 to 5.1
export JFSCHAN=5.1
juicefs version -u

Options

Items	Description
-u --upgrade	Upgrade the JuiceFS client to latest version.
-r --restart	Execute seamless remount, if client is upgraded.

juicefs quota

Manage directory quota. Different from Community Edition, JuiceFS Enterprise Edition manages quota directly from the web console, and users should not directly run this command from the terminal. The purpose of this command is to stay consistent with CE interface, so that CSI Driver may approach quota management using the same code.

juicefs heal

Repair data when using data replication. Execute a bidirectional synchronization on object storage for both file system.

Synopsis

juicefs heal VOL-NAME [options]

Option

Items	Description
--start=value	Specify object storage key range.
--upload-limit=0	Maximum bandwidth for upload in Mbps, default to 0 (unlimited).
--conf-dir=/root/.juicefs	a directory for configuration (default: /root/.juicefs)

Inspector

juicefs status

Show status of JuiceFS.

Synopsis

juicefs status [command options] VOLUME-NAME

juicefs status $VOL_NAME

Options

Items	Description
--session=0 -s 0	Show detailed information of one session, specified using a session ID (get from the SID field from the status output).

juicefs stats

The stats command reads the metrics of the JuiceFS client and prints the changes of each metric per second. You can change the --schema and --verbosity to change output format and verbosity level, -l 1 --schema=ufmcaro would print all available information, which looks like:

$ juicefs stats -l 1 --schema="ufmcaro" /jfs
---------usage--------- ----------fuse--------- ----------meta--------- ----blockcache--- -------------readahead------------ ------------------------------remotecache------------------------------ ------------------------object-----------------------
 cpu   mem   buf  cache| ops   lat   read write| ops   lat   send  recv| read write evict| used winvl wclup wshrk wfree wclos| read  rd_c  lat  write  wr_c  lat   db_c  lat   pr_c  lat   wb_c  lat | get  get_c  lat   put  put_c  lat   del  del_c  lat
 0.0%  124M   32M   44M|   0     0     0     0 |   0     0     0     0 |   0     0     0 |   0     0     0     0     0     0 |   0     0     0     0     0     0     0     0     0     0     0     0 |   0     0     0     0     0     0     0     0     0

Metrics description of each section:

usage:

• cpu: CPU usage of the process.
• mem: Physical memory used by the process.
• buf: Current buffer size, if this value is constantly close to (or even exceeds) the configured --buffer-size, you should increase buffer size or decrease application workload.

fuse:

• ops/lat: operations processed by FUSE per second, and their average latency (in milliseconds)
• read/write: read/write bandwidth usage of FUSE. Note that read stats at FUSE level doesn't necessarily equal to actual application read traffic: after files are read, the data will enter kernel page cache so that subsequent reads bypass FUSE completely, causing a lower read value, or even 0

meta:

• ops/lat: metadata operations processed per second, and their average latency (in milliseconds). Note that operations returned directly from cache are not counted in, in order to show a more accurate latency of clients actually interacting with metadata engine.

blockcache:

blockcache stands for local cache data, if read requests are already handled by kernel page cache, they won't be counted into the blockcache read metric. If there's consistent blockcache read traffic while you are conducting repeated read on a fixed file, this means read requests never enter page cache, and you should probably troubleshoot in this direction (e.g. not enough memory).

• read/write: read/write bandwidth of client local data cache

readahead：

Wasted readahead data metrics, when faced with unwanted read amplification, use metrics provided in this section to determine if there's wasted data, and the cause of the waste.

• used: Readahead data that's actually read (not wasted).
• winvl：w stands for wasted, invl stands for invalid, this indicates readahead data that's invalidated due to file being modified.
• wclup：clup stands for cleanup, readahead data isn't necessarily read, if application read range doesn't intersect at all, data will be discarded and counted against this metric.
• wshrk：shrk stands for shrink, when available buffer size is low, data is actively discarded, and counted against this metric.
• wfree：Wasted readahead data that's caused by other reasons, for example, readahead window can grow and shrink according to sequential read speed. If window size reduces, unread data is discarded and counted against this metric.
• wclos：Wasted data due to file being closed.

remotecache：

Distributed cache metrics.

• read/rd_c/lat: Read traffic from cache group, number of requests, latency.
• write/wr_c/lat: Write traffic towards cache group, number of requests, latency.

object:

object stands for object storage related metrics, when cache is enabled, penetration to object storage will significantly hinder read performance, use these metrics to check if data has been fully cached. On the other hand, you can also compare object.get and fuse.read traffic to get a rough idea of the current read amplification status.

• get/put: Get/Put bandwidth between client and object storage

For more introduction and usage of this command, see "Real-time Performance Monitoring".

Synopsis

juicefs stats [options] MOUNTPOINT

Options

Items	Description
--schema=ufmco	A schema string that controls the output format, default to “ufmcro”, its meaning: u: usage f: FUSE m: meta c: blockcache r: remotecache o: object a: readahead g: go
--interval=1	Update interval in seconds, default to 1.
--verbosity=0 -l 0	Verbosity level, use -l 1 to display more information. Specially, when readahead information is displayed, -l 1 shows very detailed metrics that could be used to determine why readahead data is wasted.

juicefs profile

Performs basic profiling based on access log, and writes comprehensive statistics to command line output. Use this command to quickly identify the overall file system access pattern of your application, and assess performance.

For more introduction and usage of this command, see "Real-time Performance Monitoring".

Synopsis

juicefs profile [command options] MOUNTPOINT/LOGFILE

# Run profile on specified path, assuming JuiceFS mount point is /mnt/jfs rather than the default /jfs
juicefs profile /mnt/jfs

# Run profile on offline access log that's collected in advance
cat /jfs/.oplog > /tmp/op.log
juicefs profile /tmp/op.log

Options

Items	Description
-g GROUP_BY --group-by=GROUP_BY	Group the output by a specific attribute, default to cmd, choose from uid, pid, cmd.
-s SORT_BY --sort-by=SORT_BY	Sort the output by a specific column, default to total_time, choose from group, number, avg_time, total_time.
-u FILTER_BY_UID --filter-by-uid=FILTER_BY_UID	Filter the output by one or multiple keywords on the UID column, please separate multi keywords by comma (,).
-p FILTER_BY_PID --filter-by-pid=FILTER_BY_PID	Filter the output by one or multiple keywords on the PID column, please separate multi keywords by comma (,).
-w WINDOW_SIZE --window-size=WINDOW_SIZE	Analysis time window, accept float value, default to 60 seconds.
-i FLUSH_INTERVAL --flush-interval=FLUSH_INTERVAL	Flush output interval, accept float value, default to 2 seconds.

juicefs info

Show internal information of a path or inode.

Synopsis

juicefs info [command options] PATH/INODE

# Lookup single file
juicefs info /mnt/jfs/foo

# Lookup directory
juicefs info -r /mnt/jfs/bar/

# Lookup file information through inode
cd /mnt/jfs
juicefs info -i 100

Options

Items	Description
PATH/INODE	Target file path or inode.
-i --inode	Lookup file information through inode. Note that the current directory must be in the JuiceFS mount point.
-r --recursive	Recursively obtain information about all subdirectories and files in a directory.
--raw	Show internal raw information.

juicefs summary

Show tree summary of target directory.

Synopsis

juicefs summary [command options] PATH

# Show with path
juicefs summary /jfs/foo

# Show max depth of 5
juicefs summary --depth 5 /jfs/foo

# Show top 20 entries
juicefs summary --entries 20 /jfs/foo

Options

Items	Description
--depth=2 -d 2	Depth of tree to show, 0 means only show root, defaults to 2.
--entries=10 -e 10	Show top N entries, sort by size, defaults to 10.
--csv	Print summary in csv format.

juicefs doctor

Collect abundant debug information, including access log, client log, CPU stats, Goroutine stacktraces. When run into unexpected situations, JuiceFS team may asks you to collect information with this command, and send back the result to continue support.

We encourage you to also take a look at Troubleshooting Methods and Troubleshooting Cases, and try to solve some of the more frequently encountered problems by yourself.

Synopsis

juicefs doctor MOUNTPOINT

juicefs lsof

List recently (within 10 minutes) opened files in JuiceFS.

Synopsis

juicefs lsof PATH

Service

juicefs mount

Mount the file system. You must provide the token of the file system (check the "File System Settings" in the website console), and the key pair to access the object storage (refer to How to Get Object Storage Access Key and Secret Key for details).

If the configuration file is not generated by the auth subcommand before mounting the file system, the client will ask you to provide the file system token and the key pair to access the object storage API separately through command line interaction.

You can mount JuiceFS as root or normal user, but due to permission issues, cache and client log locations will be different, read option descriptions below for more.

Synopsis

juicefs mount NAME MOUNTPOINT [options]

Options

Items	Description
NAME	The name of your file system.
MOUNTPOINT	The mount point for your file system.
--background -b -d	Run in the background mode, which is the default behavior.
--foreground -f	Run in the foreground mode. Client logs will print directly to the console, often used in debugging.
--no-syslog	Disable syslog.
--log=PATH	Log file location, defaults to /var/log/juicefs.log (when running as root) or ~/.juicefs/log/juicefs.log (when running as normal user).
--update-fstab	add or update entry in /etc/fstab, when applicable, see Auto-mount on boot.
--max-space	Set a maximum space limit in GiB. When you use PAYG plans, there is no real capacity limit. You may set a limit using this argument to display a sensible value in df -h output.
--prefix-internal	Add a .jfs prefix to all internal files, for example, .jfs.stats, .jfs.config.
--hide-internal	Hide all internal files (for example, .accesslog, .stats).
--sort-dir	Sort entries within a directory by name. This does not affect the output of ls and other similar tools, as the tools perform sorting themselves. This feature is intended for systems like nfsd which paginate readdir results. JuiceFS by default does not guarantee the order of directory entries. Enabling this flag to sort by name ensures that the JuiceFS client can work with nfsd.
--token=TOKEN	Specify client access token.
--no-update	Client will by default obtain latest config from JuiceFS Web Console, set to true to disable this behavior, and then client will no longer talk to JuiceFS Console when mounting.
--umask=0022	Specify the umask of the file system, which is used to adjust the default permissions when creating new directories and files. The default value is 0022 (note that the first 0 cannot be omitted, indicating that this is an octal number). For example, if set to 0000, the default permission for the new directory is 777, and the default permission for the new file is 666.
--schedule-priority=nice	Specify the nice value of the client's main process. The range that can be set with -20~99.
--no-sync	When the --Bucket2 is set, the bucket data will be bi-directionally synchronized every 7 days, enable --no-sync parameter can disable this behaviour. This parameter is usually used in a limited bandwidth environment to reduce unnecessary network traffic. Note that even if this parameter is enabled, the mirror cluster will still be notified to pull data blocks for files changed in the source cluster, they data can still keep consistency, but there will no longer be a situation where the source cluster pulls data from the mirror cluster. Users can sync the two buckets manually ondemand.

FUSE options

Items	Description
--enable-xattr	Enable extended attributes (xattr) support, default to false, which is recommended for most scenarios because xattr comes with its own overhead.
--enable-acl	Enable POSIX ACL support, see Extended ACL (requires Linux Kernel 4.9 or above).
--no-bsd-lock	Disable BSD lock support.
--no-posix-lock	Disable POSIX lock support.
--block-interrupt=1	Set the number of seconds to block interruptions (default: 1).
--readdir-cache	Set readdir caching in the kernel (requires Linux kernel 4.20+). Default is false.
--allow-other	Allow access from other users. This option is enabled by default for root users. You need to enable this feature explicitly otherwise.
--max-write Added in v5.1.0	Set the maximum size for FUSE read and write requests (requires kernel 4.20+; capped at 1 MiB). Default is "128K". If there is no other bottleneck, increasing this value can increase large file write performance but may affect random write performance. Note this parameter also applies to the maximum size for FUSE read requests, use it cautiously.
-o FUSE_OPTS	Other FUSE options. For example, enabling FUSE write cache through -o writeback_cache can greatly improve the performance of random writes and fragmented writes (requires Linux Kernel 3.15 or above). See FUSE Mount Options for a quick overview and Community Edition details.

Metadata options

Items	Description
--subdir=SUBDIR	Specify a sub-directory for mount, you can also create ACL to restrict client access to specific sub-directories, learn more at Client Access Control

Metadata cache options

Items	Description
--metacacheto=METACACHETO	Metadata cache timeout. Use 0 to disable (default: "5m").
--max-cached-inodes=500000	The maximum number of cached inodes (default: "500000").
--open-cache --opencache	Open files using cached metadata, default to false, which means every open operation access metadata service to check for file changes. If file is frequently opened and scarcely changed, consider enabling --opencache to further improve read performance. For the same mount point, open cache is automatically invalidated upon file modifications.
--attr-cache --attrcacheto=1	File attribute cache timeout in seconds (default: "1.0s").
--entry-cache --entrycacheto=1	File entry cache timeout in seconds (default: "1.0s").
--dir-entry-cache --direntrycacheto=1	Directory entry cache timeout in seconds (default: "1.0s").

Object storage options

Items	Description
--get-timeout=60	Max number of seconds to download an object, default to 60, may need to increase this in low bandwidth conditions, see Read / Write error.
--put-timeout=60	Max number of seconds to upload an object, default to 60, may need to increase this in low bandwidth conditions, see Read / Write error.
--ioretries=30 --io-retries=30	(default: 30) number of retries for network failure. Wait between retries increase linearly, but when set to over 30, wait becomes a fixed 10 seconds delay. The actual total timeout depends on specific timeout settings for each type of requests.
--object-clients=1 Added in v5.1.0	The number of object storage clients (default: 1). For some storage system SDKs (like Ceph), the client has a hard-coded bandwidth limit. This may cap the JuiceFS client's maximum throughput. If you cannot fully utilize host bandwidth even with a large concurrency, try to increase this value to use more object storage clients to see if you can boost performance.
--max-uploads=20	Upload concurrency, defaults to 20. This parameter also controls the concurrency of DELETE requests. Therefore, if the cleanup of massive amounts of data pending deletion is too slow, increasing upload concurrency can also help accelerate the process. This is already a reasonably high value for 4MiB writes, with such write pattern, increasing upload concurrency usually demands higher --buffer-size, learn more at Read/Write Buffer. But for random writes around 100K, 20 might not be enough and can cause congestion at high load, consider using a larger upload concurrency, or try to consolidate small writes in the application end.
--max-downloads=200	Max number of concurrent downloads, default to 200, which is usually large enough for clients and does not require further adjustments. This option controls client global download concurrency, but for single file read, a hard limit of 128 blocks is imposed to avoid uncontrolled resource usage in large file sequential scenarios.
--max-deletes=-1 --delete-limit=-1	Maximum QPS for deletion, default to -1 (unlimited), set to 0 to disable deletion. Use this if for example, some object storage limit API calls.
--flush-wait=5s	The time delay between automatic flush to object storage, default to 5 seconds. When slowly writing a big file, frequent flushes will cause fragmentation, consider increasing this delay to avoid write amplification.
--upload-limit=0	Maximum bandwidth for upload in Mbps, default to 0 (unlimited). Apart from bandwidth control, this parameter can also be used for system load control with high throughput scenarios.
--download-limit=0	Maximum bandwidth for download in Mbps, default to 0 (unlimited). Apart from bandwidth control, this parameter can also be used for system load control with high throughput scenarios.
--external	Prefer to use the external entrypoint of the object storage service. This means the traffic of JuiceFS will go through the public network instead of the internal network.
--internal	Prefer to use the internal entrypoint of the object storage service. This means the traffic of JuiceFS will go through the internal network instead of the public network. (Applicable to some object storages that separate internal and external network domain names, e.g. Aliyun OSS, UCloud UFile, etc.)
--rsa-key=PATH	Path to RSA private key (PEM). Passphrase will be asked or provided with JFS_RSA_PASSPHRASE environment variable.
--flip	When data replication is enabled, use secondary bucket as primary bucket. Learn more at Cross-region data replication.

Cache options

Read Cache to understand JuiceFS's cache design.

Items	Description
--buffer-size=300	Total size of memory used for read/write buffering in MiB default to 300, learn more at Read/Write Buffer
--prefetch=1	When a block is randomly read by a small offset range, the whole block is scheduled for download asynchronously, this is called prefetch in JuiceFS. This options controls prefetch concurrency, which defaults to 1, and can be disabled by setting to 0. Note that: Prefetch can cause read amplification in some scenarios When used with dedicated cache cluster, clients do not read from object storage directly (but through cache group members instead), so this option is meaningless for --no-sharing clients.
--max-readahead	The maximum readahead window, in MiB. Value must not exceed Block size * 128MiB, so using the default block size, that's 512MiB. If this option isn't explicitly defined, the actual readahead window is managed dynamically by buffer usage and download concurrency. Since 5.1.18, readahead behavior is significantly improved, so before you continue with the content of this section, we advise you to upgrade your JuiceFS Client and see if the unexpected read amplification goes away, before moving on to change this option.
--readahead-ratio	Adjust readahead ratio, defaults to 1.0. Use a float number between 0~1 to further suppress read amplification. This is mostly used in large file random read cases. Since 5.1.18, readahead behavior is significantly improved, so before you continue with the content of this section, we advise you to upgrade your JuiceFS Client and see if the unexpected read amplification goes away, before moving on to change this option.
--initial-readahead	The initial readahead for sequential reads in MiB. Use a larger value to boost large file sequential read performance. If this option is not specified, the default readahead window is 4096 bytes.
--writeback	Enable client write cache, data will be written to local disk first, and then uploaded asynchronously in the background, default to false. Client write cache brings data security risks, use with caution.
--cache-dir=CACHEDIR	Cache directory, defaults to /var/jfsCache or $HOME/.juicefs/cache depending on the current user. Separate multiple directories by :, add quotation mark if using wildcard match (*). e.g. --cache-dir '/data*/jfsCache:/mydata*/jfsCache'. Moreover, you can specify /dev/shm to use the memory device (defaults to half of the host's memory), or use the string memory to use client process memory. When client starts, it scans all the block files under the cache directories and index them in process memory, if more than one JuiceFS Client reuses the same directory as cache storage, they will not discover cache data contributed by others. And if multiple clients apply different cache size (--cache-size and --free-space-ratio), the smallest value becomes the eviction threshold, so A's cache data can be evicted by B.
--cache-size=102400	Local cache size limit in MiB. The default value is 102400 (100GiB), set this value to -1 to use the disk size as cache size (supported since 5.1). When multiple directories are used as the cache directory, --cache-size limits the total size sum (split evenly). You can set it to 0 to disable disk cache altogether, but this causes an extra 100MB memory overhead to grant the client a minimum cache space, when disk read requests frequently fail, the client process stops using local cache disk and fall back to the minimum 100MB memory cache, this can also be reflected in cache read metrics, which will plummet to 100MB or less.
--free-space-ratio=0.1	Minimum free space ratio on cache disk, default to 0.1 (0.2 for 4.9 and older versions). This option doesn't support being set to 0, to achieve maximum usage, you can set a value close to 0 (such as 0.01). Also if Client write cache is enabled, this option also controls write cache size
--cache-mode=0600	File permission for cached blocks, default to 0600.
--cache-partial-only	For the read cache, only data blocks smaller than one block size (default 4MiB) are cached, such as small files smaller than one block size, and data blocks smaller than one block size at the end of large files. The default value is false (that is, all read data blocks are cached). Note that this option will also affect the cache construction of Distributed Cache. Read client read cache to learn more.
--cache-large-write Added in v5.1.0	Cache full blocks from write. By default, JuiceFS does not cache large sequential writes (they were not read in most scenarios). You can enable this flag to cache them when needed.
--verify-cache-checksum=extend	Checksum level for cache data. After enabled, checksum will be calculated on divided parts of the cache blocks and stored on disks, which are used for verification during reads. The following strategies are supported: none: Disable checksum verification, if local cache data is tampered, bad data will be read; full: Perform verification when reading the full block, use this for sequential read scenarios; shrink: Perform verification on parts that's fully included within the read range, use this for random read scenarios; extend (default): Perform verification on parts that fully include the read range, this causes read amplifications and is only used for random read scenarios demanding absolute data integrity.
--cache-eviction=2-random Added in v5.0.1	Cache eviction algorithm, supports the following strategies: 2-random (default): Evict cache using 2-random algorithm, i.e. randomly choose two blocks, and evict the one with a lower atime (last access time). For most real-world scenarios, this algorithm approximates LRU. none: Disable cache eviction altogether, new cache will not write once cache capacity is drained. You'll have to manually free up cache space.
--cache-expire=0s Added in v5.1.0	Cached blocks not accessed for longer than the specified duration will be automatically evicted (0 means never; default: "0s").

Distributed cache options

Read distributed cache for more.

Items	Description
--cache-group=CACHEGROUP	Cache group name for distributed cache. Nodes within the same group share cache, disabled by default.
--subgroups=0	Further divide cache group into smaller sub-groups, default to 0. When changed to integers above 0, the cache group becomes N sub-groups, all carrying a numbered prefix in their group name. When there's a large number of clients within the group, there could be data hotspots (for example, when all clients try to access the same 4M block) and cause cache group provider network to congest. You can use --subgroups=10 to create 10 sub-groups, so that clients turn to access data in their smaller sub-group, to reduce the possibility of a data hotspot. The drawback of this feature is data redundancy, make sure you plan cache capacity properly.
--group-network	Network interface for distributed cache. Default listening IP is the first private IP found in the network device list, if this isn't appropriate for you, use this option to specify a fixed network interface.
--group-ip=GROUPIP	Manually set IP address listened by distributed cache, in hosts with multiple network interfaces, use this option to specify the correct NIC. Can also use CIDR prefix to automatically select IP, e.g. use 172.16.0.0 to match with 172.16.0.0/16.
--group-port	Listen port for distributed cache, defaults to a large random port. If the specified port doesn't work, will automatically increase by 1 until a successful bind.
--group-weight=100	When using hosts with different disk sizes, use this setting to adjust group member weight. Recommended value range is 10 to 1000, that's to say for example, a cache group consists of a 1TB host and a 3TB host, you can use 100 weight for the 1TB host and 300 for the 3TB host.
--group-weight-unit=0	If you prefer not to manually set --group-weight and instead want it to be automatically derived from --cache-size, you can specify this parameter. The unit is MiB. For example, with the default --cache-size=102400 and --group-weight-unit=1024, where the latter means "1 weight equals 1024 MiB," the final weight will be 102400 / 1024 = 100.
--group-backup	Enable the group backup feature. When enabled, if a node's local cache is not hit, it forwards the request to other nodes. Once the request is fulfilled, both the original and the responding nodes attempt to cache the data locally. For more details on the principle and use cases, see Group backup
--no-sharing	When inside a cache group, only fetch cache data from others, but never share its own cache. Use this option on ephemeral mount points (like Kubernetes Pod). Default to false.
--fill-group-cache	Send written data blocks to the cache group as much as possible (100% caching is not guaranteed) and no longer write to the local cache. Be aware that: When used with --no-sharing, clients will only contribute writes smaller than block size (4MiB by default) to the cache group, because often times sequential read large files provide poor caching value, but can consume space quickly. If you wish to contribute writes larger than block size to the cache cluster as well, use --cache-large-write. Since 4.9.22, if client write cache is enabled, the staging data will be sent asynchronously to the cache group as well, no matter its size, so that cache group members have a good chance of reading data that's not yet persisted.
--cache-group-size=0	Unit is MiB. JuiceFS Client performs readahead and prefetch, so for files smaller than this size, client will try to schedule all its data blocks into a single node, to maximize cache utilization.
--cache-priority=0 Added in v5.0.14	The priority of the cache block. The available values ​​are: 0, 1, 2, and 3. The larger the number, the higher the priority. When cache is evicted, data with lower priority will be evicted first.
--remote-timeout=65s Added in v5.1.0	Timeout duration for cache group requests (default: 65 seconds).
--group-compress Added in v5.1.0	Compress the network traffic between peers, enabled by default. You can disable it to save some CPU overhead when compression ratio for your data is low. Starting from 5.2.0, this is disabled by default.

Experimental options

warning

These options are currently experimental and subject to change in the future. Incorrect usage may pose data integrity risks, if you do need to run this command, seek help from a Juicedata engineer.

Items	Description
--min-inodes-diff=1048576	When the inodes difference between the current zone and the zone with the least inodes exceeds this value, the metadata will be automatically balanced. Defaults to 1048576.
--min-dir-inodes=1048576	When the number of directories in the current path exceeds this value, the metadata is automatically balanced. Defaults to 1048576.
--max-space=0	Limit the displayed total space in GiB, defaults to 0, meaning that the true total capacity is displayed.

Windows-Related options

warning

The Windows version is currently in beta, and the options below may change slightly in the future.

Items	Description
-o	Additional WinFsp mount options.
--log	Path to the log file when running in the background.
--as-root	Mount the volume as root. When enabled, all file operations use UID=0 and GID=0.
--ignoreGid	Ignore the GID field in file attributes.
-f	Mount in the foreground. Defaults to false. Note: when mounting in the background, JuiceFS runs as a system service, which requires administrator privileges.
--show-dot-files	Show hidden files (those beginning with a dot). Defaults to false.
--winfsp-threads	Number of threads WinFsp uses to process kernel messages. Defaults to max(CPU*2, 16).
--report-case	When set, JuiceFS will report the actual case-sensitive paths back to Windows wherever possible. (May impact performance.)
--enable-kernel-cache	When enabled, JuiceFS will instruct WinFsp to use the Windows Kernel Cache Manager, improving read performance in some scenarios. However, commands like profile and stats may not work. Defaults to false.
--alias	Alias for the volume. Use this if you want to mount the same volume to different drive letters on the same machine. Defaults to empty.

juicefs umount

Umount a JuiceFS file system. This command handles the platform differences, i.e. umount in Linux and diskutil unmount in macOS. Note that there's a similar hidden command called juicefs unmount, this is specially reserved for Kubernetes FlexVolume and not for normal use.

If you encounter any errors while unmounting JuiceFS, read the docs for troubleshooting steps.

Synopsis

juicefs umount PATH [options]

Options

Items	Description
PATH	The mount point for your file system.
-f --force	Umount it forcibly.

juicefs gateway

Start an S3 gateway, read S3 gateway for more.

Synopsis

juicefs gateway [command options] VOLUME-NAME ADDRESS

export MINIO_ROOT_USER=admin
export MINIO_ROOT_PASSWORD=12345678
juicefs gateway testVolume localhost:9000

Options

Apart from options listed below, this command shares options with juicefs mount, be sure to refer to mount as well.

Flag	Description
--console-url=URL	Web URL address, only needed in on-premise environments.
--mountpoint=s3gateway	Specify the JuiceFS mount point on host, needed only for absolute symlink resolution, defaults to s3gateway. See S3 Gateway and symbolic link.
--access-log=PATH	Path for file system access log, default location is the .accesslog file under the root mount point.
--no-banner	Omit MinIO startup messages.
--multi-buckets	Use top level directories as buckets, default to false.
--keep-etag	Keep object ETag when uploading.
--umask="0022"	Umask used for new files, default to 0022.

juicefs webdav

Start a WebDAV server to access JuiceFS file system.

Use the environment variable WEBDAV_USERNAME and WEBDAV_PASSWORD to set the username and password for WebDAV server.

Synopsis

juicefs webdav [command options] NAME ADDRESS

# Set username and password
export WEBDAV_USER=root
export WEBDAV_PASSWORD=1234

# Start WebDAV server on port 9007
juicefs webdav myjfs localhost:9007

Options

Apart from options listed below, this command shares options with juicefs mount, be sure to refer to mount as well.

Items	Description
--cert-file	certificate file for TLS
--key-file	key file for TLS

Tool

juicefs benchmark

Run single benchmark, including read/write/stat big/small files.

Synopsis

juicefs benchmark [options] path-to-test

Options

Items	Description
--dest=/jfs/benchmark	Temporary directory for benchmark test files, default to /jfs/benchmark.
--block-size=BLOCK_SIZE	(default: 1MiB) block size in MiB
--bigfile-file-size=BIGFILE_FILE_SIZE	(default: 1024MiB) size of big file in MiB
--smallfile-file-size=SMALLFILE_FILE_SIZE	(default: 0.1MiB) size of small file in MiB
--smallfile-count=100	(default: 100) number of small files

juicefs objbench

Run basic benchmarks on the target object storage to test if it works as expected.

Synopsis

juicefs objbench [command options] BUCKET

Options

Items	Description
--storage=file	Object storage type (e.g. s3, gcs, oss, cos) (default: file)
--access-key=value	Access Key for object storage (can also be set via the environment variable ACCESS_KEY)
--secret-key value	Secret Key for object storage (can also be set via the environment variable SECRET_KEY)
--session-token=value	Session token for object storage
--block-size=4096	size of each I/O block in KiB (default: 4096)
--big-object-size=1024	size of each big object in MiB (default: 1024)
--small-object-size=128	size of each small object in KiB (default: 128)
--small-objects=100	number of small objects (default: 100)
--skip-functional-tests	skip functional tests (default: false)
--threads=4, -p 4	number of concurrent threads (default: 4)
--object-clients=1 Added in v5.1.0	refer to 「JuiceFS mount Object storage options」

juicefs warmup

Download data to local cache in advance, to achieve better performance on application's first read. You can specify a mount point path to recursively warm-up all files under this path. You can also specify a file through the --file option to only warm-up the files contained in it.

If the files needing warming up resides in many different directories, you should specify their names in a text file, and pass to the warmup command using the --file option, allowing juicefs warmup to download concurrently, which is significantly faster than calling juicefs warmup multiple times, each with a single file.

The warmup command will not repeatedly download files that already exist locally (it will be skipped directly), so the displayed download speed may be higher than the actual download traffic. If the distributed cache is enabled, executing this command on any node in the cache group can achieve the same effect.

Synopsis

juicefs warmup [PATH] [options]

# Warm up all files in datadir
juicefs warmup /mnt/jfs/datadir

# Warm up selected files
echo '/jfs/f1
/jfs/f2
/jfs/f3' > /tmp/filelist.txt
juicefs warmup -f /tmp/filelist.txt

Options

Items	Description
--file=FILE -f FILE --listfile=FILE	file containing a list of paths (one path per line)
--threads=50 -p 50 -c 50 --concurrent=50	Download concurrency, default to 50. Increase concurrency to speed up, but if the download bandwidth of the object storage is low, reduce concurrency to avoid download timeout errors. If you're experience warmup slowness in distributed cache cluster, try increasing this value starting from 20 * [number of cache group members] and find a suitable concurrency.
--cache-priority=0 Added in v5.0.14	The priority of the cache block. The available values ​​are: 0, 1, 2, and 3. The larger the number, the higher the priority. When cache is evicted, data with lower priority will be evicted first.
--io-retries=1	Max number of allowed retries, default to 1. Increase this value in poor network conditions to better handle failures.
--max-failure=0	Controls the command exit code according to the number of download failures, the number of allowed failures is default to 0, meaning that upon any data block warmup failure, command exits with error (exit code 1). When faced with warmup errors, check client logs for troubleshooting.
--background -b	Run in the background.
--evict	Evict cached blocks for given path.
--check	check whether the data blocks for the given path are cached or not.

juicefs clone (juicefs snapshot)

This command takes a snapshot of your data by creating a mere metadata copy, without creating any new data in the object storage, thus snapshotting is very fast regardless of target file / directory size. Under JuiceFS, this command is a better alternative to cp, moreover, for Linux clients using kernels with copy_file_range support, then the cp command achieves the same result as juicefs snapshot.

Snapshot result is a metadata copy, all the files are still referencing the same object storage blocks, that's why a snapshot behaves the same in every way as its originals. When either of them go through actual file data modification, the affected data blocks will be copied on write, and become new blocks after write, while the unchanged part of the files remains the same, still referencing the original blocks.

Some caveats when using this feature:

• Although object storage data is not actually copied, snapshots takes up storage space, and will result in an increase in bill, pay special attention when taking snapshots on large size directories.
• Cloning a large directory takes time, if content changes (files are deleted, moved, etc.) during this period, the command complains no such file error, this is completely normal.
• JuiceFS volumes are isolated from each other, snapshots cannot be created across file systems.

Synopsis

juicefs snapshot SRC DST [-f|--force] [-c|--copy]  # create a snapshot
juicefs snapshot -d DST [-f|--force]  # delete a snapshot

Options

Items	Description
SRC	The path to the file you are creating the snapshot from.
DST	The locate where you want to store your snapshot.
-d --delete	Remove the snapshot. Only use this command on snapshots, deleting normal files using this command will result in permission errors. Deleted snapshots will bypass Trash completely. If you want to preserve the deleted snapshots in Trash like normal files, use juicefs rmr or simply rm -r.
-f --force	Overwrite existing snapshot, or remove the snapshot arbitrarily.
-c --copy	Use current user's UID, GID and umask to create the snapshot. Otherwise it will use permission information of the file you are creating snapshot.

juicefs rmr

Remove all the files and subdirectories, similar to rm -rf, except this command deals with metadata directly (bypassing POSIX API), thus is much faster.

It will try to remove them using current UID/GID, ignore those that can't be removed, return the number of removed files/directories, the number of left ones.

If trash is enabled, deleted files are moved into trash. Files inside trash is still billable, read more at trash.

Synopsis

juicefs rmr DIR

Options

Items	Description
DIR	Files to delete.
--skip-trash	Skip the trash and delete directly, used when in urgent need to release object storage capacity. Use cautiously.

juicefs sync

Sync data between two storage systems, read Data Migration for more.

Synopsis

juicefs sync [command options] SRC DST

# Sync object from OSS to S3
juicefs sync oss://mybucket.oss-cn-shanghai.aliyuncs.com s3://mybucket.s3.us-east-2.amazonaws.com

# Sync objects from S3 to JuiceFS
juicefs sync s3://mybucket.s3.us-east-2.amazonaws.com/ jfs://VOL_NAME/

# SRC: a1/b1,a2/b2,aaa/b1   DST: empty   sync result: aaa/b1
juicefs sync --exclude='a?/b*' s3://mybucket.s3.us-east-2.amazonaws.com/ jfs://VOL_NAME/

# SRC: a1/b1,a2/b2,aaa/b1   DST: empty   sync result: a1/b1,aaa/b1
juicefs sync --include='a1/b1' --exclude='a[1-9]/b*' s3://mybucket.s3.us-east-2.amazonaws.com/ jfs://VOL_NAME/

# SRC: a1/b1,a2/b2,aaa/b1,b1,b2  DST: empty   sync result: a1/b1,b2
juicefs sync --include='a1/b1' --exclude='a*' --include='b2' --exclude='b?' s3://mybucket.s3.us-east-2.amazonaws.com/ jfs://VOL_NAME/

Both SRC and DST takes up the format [NAME://][ACCESS_KEY:SECRET_KEY[:SESSIONTOKEN]@]BUCKET[.ENDPOINT][/PREFIX], in which:

• NAME: Can be all JuiceFS supported storage, e.g. s3, oss, even jfs. Using jfs:// allows you to directly transfer data from or into JuiceFS, bypassing the FUSE mount point, this saves resource under large scale data transfer.
• ACCESS_KEY and SECRET_KEY: Object storage credentials, special characters need to be URL encoded, e.g. / must be substituted with %2F.
• SESSIONTOKEN: Optionally provide session token for the object storage.
• BUCKET[.ENDPOINT]: Object storage endpoint, note that currently MinIO only supports path style (minio://[ACCESS_KEY:SECRET_KEY[:TOKEN]@]ENDPOINT/BUCKET[/PREFIX]).
• [/PREFIX]: Optionally provide the prefix of the files to synchronize.

tip

Apart from options listed below, this command shares options with juicefs mount, be sure to refer to mount as well.

Do notice that many of these shared options works exclusively with jfs scheme, for example, the sync command supports --writeback as well, but if the sync destination is a normal JuiceFS FUSE mount point, it won't automatically convert itself to a --writeback mount point simply because you are running a sync job with --writeback. To sum up, --writeback only works when sync destination is a jfs scheme address, and this is also true for many other options that's shared with mount.

Selection related options

Items	Description
--start=KEY, -s KEY, --end=KEY, -e KEY	Provide object storage key range for syncing.
--exclude=PATTERN	Exclude keys matching PATTERN.
--include=PATTERN	Include keys matching PATTERN, need to be used with --exclude.
--limit=-1	Limit the number of objects that will be processed, default to -1 which means unlimited.
--update, -u	Update existing files if the source files' mtime is newer, default to false.
--force-update, -f	Always update existing file, default to false.
--existing, --ignore-non-existing	Skip creating new files on destination, default to false.
--ignore-existing	Skip updating files that already exist on destination, default to false.
--files-fromAdded in v5.1.10	Read item list from a text file, each item in the text file will be concatenated with the command line source & destination arguments to form the full path. For instance, to sync /jfs1/data.tar towards /jfs2/data.tar, the text file would contain /data.tar, save this file to files.txt and you can run juicefs sync --files-from=files.txt /jfs1 /jfs2.

Action related options

Items	Description
--dirs	Sync empty directories as well, default to false. Object storage lacks the concept of "directory", so by default juicefs sync doesn't copy empty directories. If source & destination is both file systems, then --dirs should usually be used to preserve empty directories.
--perms	Preserve ownership and permissions, default to false. This option doesn't affect directories, if you'd like to preserve ownership and permissions for both file and directory, use --dirs as well.
--inplace	Modify files in place, rather than delete and replace. If destination storage system is a JuiceFS volume with Trash enabled, overwritten files by default will be kept in Trash. Use --inplace to modify files in place and prevent Trash usage. Currently only jfs:// type destination storage is supported.
--links, -l	Copy symlinks as symlinks default to false.
--delete-src, --deleteSrc	Delete objects that already exist in destination. Different from rsync, files won't be deleted at the first run, instead they will be deleted at the next run, after files are successfully copied to the destination.
--delete-dst, --deleteDst	Delete redundant objects in destination (i.e., files that exist in the dest but not in the source storage). You can use this option if you want the target to be exactly the same as the source, the extra files in the target will be deleted.
--check-all	Verify the integrity of all files in source and destination, default to false. Comparison is done on byte streams, which comes at a performance cost.
--check-new	Verify the integrity of newly copied files, default to false. Comparison is done on byte streams, which comes at a performance cost.
--check-changeAdded in v5.2.0	Verify whether the data has changed before and after synchronization, default is false. Based on file size and mtime, which is lightweight.
--max-failureAdded in v5.2.0	max number of allowed failed files (-1 for unlimited)
--dry	Don't actually copy any file.
--http-port=6070	HTTP port for the pprof server to listen on, default to 6070.

Storage related options

Items	Description
--threads=10, -p 10	Number of concurrent threads, default to 10. Higher concurrency requires more resource, particularly in large file scenarios, because more big files will be loaded into the process memory.
--list-threads=1	Number of list threads, default to 1. Read concurrent list to learn its usage.
--list-depth=1	Depth of concurrent list operation, default to 1. Read concurrent list to learn its usage.
--no-https	Do not use HTTPS, default to false.
--storage-class=value	Storage class for the destination storage, if supported. Read relevant docs for more, e.g. S3.
--bwlimit=0	Limit bandwidth in Mbps default to 0 which means unlimited.

Cluster related options

Items	Description
--manager=ADDR	Manager node address used in distributed syncing, this is an internal option that's used in the executed command on the worker nodes.
--worker=ADDR,ADDR	Worker node addresses used in distributed syncing, comma separated.

Metrics related options

项	说明
--metrics	Address to export metrics, defaults to 127.0.0.1:9567.
--consul	Consul address to register, defaults to 127.0.0.1:8500.

juicefs import

juicefs import scans the target object storage bucket, collects metadata of the existing files, and saves to the JuiceFS metadata engine. This gives JuiceFS access to the existing object storage files, but the file data will remain in the object storage as is. To learn more, see Import existing object storage files.

Synopsis

tip

Caching isn't supported for external buckets. This means in order to have caching support, the JuiceFS volume and import source must be the same bucket, and execute the import command in the following format:

# URI doesn't include bucket name, caching is supported
juicefs import / /jfs/imported
juicefs import /prefix /jfs
# If URI contains bucket, caching is no longer supported
# In the below example, even if BUCKET is the same as the JuiceFS volume bucket, caching will not be available
juicefs import BUCKET/prefix /jfs

juicefs import URI DST [-v] [--name=<name>] [--mode=<mode>]

# Assuming the mount point being /jfs, and importing from the same bucket as the file system, in such case, the bucket name can be omitted
# But remember to use a prefix, to avoid importing data created by JuiceFS itself (the chunks directory), into JuiceFS, as it'll be meaningless inside JuiceFS
juicefs import /prefix /jfs/imported

# Assuming the bucket is in the same region as the file system
# Then the endpoint can be omitted to just the bucket name
juicefs import another-bucket/prefix /jfs/imported

# If the bucket is located in another region, the full endpoint must be specified
juicefs import other-bucket.s3.cn-northwest-1.amazonaws.com.cn /jfs

# Import files in mybucket by a prefix, into the specified directory within JuiceFS
juicefs import other-bucket/prefix /jfs/oss-imported

Options

Items	Description
URI	The object storage URI of the target, format is the BUCKET[.ENDPOINT][/PREFIX]. Must use the same type of object storage as the file system itself, and should be accessible with the same set of credentials (access key, secret key), you cannot specify separate keys within this URI.
DST	Import destination, must be a JuiceFS mount point, and the file system must be using the same object storage as the URI.
--mode=0440	The default permission for importing files is 0440 (note that the first 0 cannot be omitted, indicating that this is an octal number). This option cannot adjust the default permissions of the new directory. If you need to adjust, please use the umask command to modify it first. For example, if you want the default permissions of the new directory to be 777, you need to execute the command umask 000 && juicefs import ... in this way.
--threads=50	Number of workers. If the object storage list produces too many items, increase this value to write to metadata faster.
--list-threads=10	Number of list threads. The default value is 10. This is similar to concurrent list.
--list-depth=2	Depth of concurrent list operations. The default value is 1. This is similar to concurrent list.
--update	Only import newer files (compared using mtime).
--files-fromAdded in v5.2.0	Reads a text file to obtain the list of files to be imported; the text file can contain specific files or prefixes.
--force-update	Import and overwrite all different files. When some storage systems do not support automatic mtime update, use this option to update the import.

juicefs grep

Parallelized file pattern searcher.

Synopsis

juicefs grep [PATTERN] PATH ... [options]

Options

Items	Description
[PATTERN]	Support simple pattern and basic regular expression.
PATH	Search path and files.
-j JOBS --jobs=JOBS	Number of parallel jobs (default is number of CPU cores).
-e PATTERNS --regexp PATTERNS	This option is most useful when multiple -e options are used to specify multiple patterns, or when a pattern begins with a dash (-).
-E extended-regexp	Interpret pattern as an extended regular expression.
-H	Always print filename headers with output lines.
-n --line-number	Each output line is preceded by its relative line number in the file, starting at line 1.
-i --ignore-case	Perform case insensitive matching. By default, it is case sensitive.
-v --invert-match	Selected lines are those not matching any of the specified patterns.