---

title: "B2" description: "Backblaze B2" versionIntroduced: "v1.26"

Backblaze B2

B2 is Backblaze's cloud storage system.

Paths are specified as remote:bucket (or remote: for the lsd command.) You may put subdirectories in too, e.g. remote:bucket/path/to/dir.

Configuration

Here is an example of making a b2 configuration. First run

rclone config

This will guide you through an interactive setup process. To authenticate you will either need your Account ID (a short hex number) and Master Application Key (a long hex number) OR an Application Key, which is the recommended method. See below for further details on generating and using an Application Key.

No remotes found, make a new one\?
n) New remote
q) Quit config
n/q> n
name> remote
Type of storage to configure.
Choose a number from below, or type in your own value
[snip]
XX / Backblaze B2
   \ "b2"
[snip]
Storage> b2
Account ID or Application Key ID
account> 123456789abc
Application Key
key> 0123456789abcdef0123456789abcdef0123456789
Endpoint for the service - leave blank normally.
endpoint>
Remote config
Configuration complete.
Options:
- type: b2
- account: 123456789abc
- key: 0123456789abcdef0123456789abcdef0123456789
- endpoint:
Keep this "remote" remote?
y) Yes this is OK
e) Edit this remote
d) Delete this remote
y/e/d> y

This remote is called remote and can now be used like this

See all buckets

rclone lsd remote:

Create a new bucket

rclone mkdir remote:bucket

List the contents of a bucket

rclone ls remote:bucket

Sync /home/local/directory to the remote bucket, deleting any excess files in the bucket.

rclone sync --interactive /home/local/directory remote:bucket

Application Keys

B2 supports multiple Application Keys for different access permission to B2 Buckets.

You can use these with rclone too; you will need to use rclone version 1.43 or later.

Follow Backblaze's docs to create an Application Key with the required permission and add the applicationKeyId as the account and the Application Key itself as the key.

Note that you must put the applicationKeyId as the account – you can't use the master Account ID. If you try then B2 will return 401 errors.

--fast-list

This remote supports --fast-list which allows you to use fewer transactions in exchange for more memory. See the rclone docs for more details.

Modification times

The modification time is stored as metadata on the object as X-Bz-Info-src_last_modified_millis as milliseconds since 1970-01-01 in the Backblaze standard. Other tools should be able to use this as a modified time.

Modified times are used in syncing and are fully supported. Note that if a modification time needs to be updated on an object then it will create a new version of the object.

Restricted filename characters

In addition to the default restricted characters set the following characters are also replaced:

Invalid UTF-8 bytes will also be replaced, as they can't be used in JSON strings.

Note that in 2020-05 Backblaze started allowing \ characters in file names. Rclone hasn't changed its encoding as this could cause syncs to re-transfer files. If you want rclone not to replace \ then see the --b2-encoding flag below and remove the BackSlash from the string. This can be set in the config.

SHA1 checksums

The SHA1 checksums of the files are checked on upload and download and will be used in the syncing process.

Large files (bigger than the limit in --b2-upload-cutoff) which are uploaded in chunks will store their SHA1 on the object as X-Bz-Info-large_file_sha1 as recommended by Backblaze.

For a large file to be uploaded with an SHA1 checksum, the source needs to support SHA1 checksums. The local disk supports SHA1 checksums so large file transfers from local disk will have an SHA1. See the overview for exactly which remotes support SHA1.

Sources which don't support SHA1, in particular crypt will upload large files without SHA1 checksums. This may be fixed in the future (see #1767).

Files sizes below --b2-upload-cutoff will always have an SHA1 regardless of the source.

Transfers

Backblaze recommends that you do lots of transfers simultaneously for maximum speed. In tests from my SSD equipped laptop the optimum setting is about --transfers 32 though higher numbers may be used for a slight speed improvement. The optimum number for you may vary depending on your hardware, how big the files are, how much you want to load your computer, etc. The default of --transfers 4 is definitely too low for Backblaze B2 though.

Note that uploading big files (bigger than 200 MiB by default) will use a 96 MiB RAM buffer by default. There can be at most --transfers of these in use at any moment, so this sets the upper limit on the memory used.

Versions

The default setting of B2 is to keep old versions of files. This means when rclone uploads a new version of a file it creates a new version of it. Likewise when you delete a file, the old version will be marked hidden and still be available.

Whether B2 keeps old versions of files or not can be adjusted on a per bucket basis using the "Lifecycle settings" on the B2 control panel or when creating the bucket using the --b2-lifecycle flag or after creation using the rclone backend lifecycle command.

You may opt in to a "hard delete" of files with the --b2-hard-delete flag which permanently removes files on deletion instead of hiding them.

Old versions of files, where available, are visible using the --b2-versions flag. These can be deleted as required with delete.

It is also possible to view a bucket as it was at a certain point in time, using the --b2-version-at flag. This will show the file versions as they were at that time, showing files that have been deleted afterwards, and hiding files that were created since.

If you wish to remove all the old versions, and unfinished large file uploads, then you can use the rclone cleanup remote:bucket command which will delete all the old versions of files, leaving the current ones intact. You can also supply a path and only old versions under that path will be deleted, e.g. rclone cleanup remote:bucket/path/to/stuff.

Note that cleanup will remove partially uploaded files from the bucket if they are more than a day old. If you want more control over the expiry date then run rclone backend cleanup b2:bucket -o max-age=1h to remove all unfinished large file uploads older than one hour, leaving old versions intact.

If you wish to remove all the old versions, leaving current files and unfinished large files intact, then you can use the rclone backend cleanup-hidden remote:bucket command. You can also supply a path and only old versions under that path will be deleted, e.g. rclone backend cleanup-hidden remote:bucket/path/to/stuff.

When you purge a bucket, the current and the old versions will be deleted then the bucket will be deleted.

However delete will cause the current versions of the files to become hidden old versions.

Here is a session showing the listing and retrieval of an old version followed by a cleanup of the old versions.

Show current version and all the versions with --b2-versions flag.

$ rclone -q ls b2:cleanup-test
        9 one.txt

$ rclone -q --b2-versions ls b2:cleanup-test
        9 one.txt
        8 one-v2016-07-04-141032-000.txt
       16 one-v2016-07-04-141003-000.txt
       15 one-v2016-07-02-155621-000.txt

Retrieve an old version

$ rclone -q --b2-versions copy b2:cleanup-test/one-v2016-07-04-141003-000.txt /tmp

$ ls -l /tmp/one-v2016-07-04-141003-000.txt
-rw-rw-r-- 1 ncw ncw 16 Jul  2 17:46 /tmp/one-v2016-07-04-141003-000.txt

Clean up all the old versions and show that they've gone.

$ rclone -q cleanup b2:cleanup-test

$ rclone -q ls b2:cleanup-test
        9 one.txt

$ rclone -q --b2-versions ls b2:cleanup-test
        9 one.txt

Versions naming caveat

When using --b2-versions flag rclone is relying on the file name to work out whether the objects are versions or not. Versions' names are created by inserting timestamp between file name and its extension.

        9 file.txt
        8 file-v2023-07-17-161032-000.txt
       16 file-v2023-06-15-141003-000.txt

If there are real files present with the same names as versions, then behaviour of --b2-versions can be unpredictable.

Data usage

It is useful to know how many requests are sent to the server in different scenarios.

All copy commands send the following 4 requests:

/b2api/v4/b2_authorize_account
/b2api/v1/b2_create_bucket
/b2api/v1/b2_list_buckets
/b2api/v1/b2_list_file_names

The b2_list_file_names request will be sent once for every 1k files in the remote path, providing the checksum and modification time of the listed files. As of version 1.33 issue #818 causes extra requests to be sent when using B2 with Crypt. When a copy operation does not require any files to be uploaded, no more requests will be sent.

Uploading files that do not require chunking, will send 2 requests per file upload:

/b2api/v1/b2_get_upload_url
/b2api/v1/b2_upload_file/

Uploading files requiring chunking, will send 2 requests (one each to start and finish the upload) and another 2 requests for each chunk:

/b2api/v1/b2_start_large_file
/b2api/v1/b2_get_upload_part_url
/b2api/v1/b2_upload_part/
/b2api/v1/b2_finish_large_file

Viewing versions with --b2-versions

Versions can be viewed with the --b2-versions flag. When it is set rclone will show and act on older versions of files. For example

Listing without --b2-versions

$ rclone -q ls b2:cleanup-test
        9 one.txt

And with

$ rclone -q --b2-versions ls b2:cleanup-test
        9 one.txt
        8 one-v2016-07-04-141032-000.txt
       16 one-v2016-07-04-141003-000.txt
       15 one-v2016-07-02-155621-000.txt

Showing that the current version is unchanged but older versions can be seen. These have the UTC date that they were uploaded to the server to the nearest millisecond appended to them.

Note that when using --b2-versions no file write operations are permitted, so you can't upload files or delete them.

B2 and rclone link

Rclone supports generating file share links for private B2 buckets. They can either be for a file for example:

./rclone link B2:bucket/path/to/file.txt
https://f002.backblazeb2.com/file/bucket/path/to/file.txt?Authorization=xxxxxxxx

or if run on a directory you will get:

./rclone link B2:bucket/path
https://f002.backblazeb2.com/file/bucket/path?Authorization=xxxxxxxx

you can then use the authorization token (the part of the url from the ?Authorization= on) on any file path under that directory. For example:

https://f002.backblazeb2.com/file/bucket/path/to/file1?Authorization=xxxxxxxx
https://f002.backblazeb2.com/file/bucket/path/file2?Authorization=xxxxxxxx
https://f002.backblazeb2.com/file/bucket/path/folder/file3?Authorization=xxxxxxxx

Standard options

Here are the Standard options specific to b2 (Backblaze B2).

--b2-account

Account ID or Application Key ID.

Properties:

• Config: account
• Env Var: RCLONE_B2_ACCOUNT
• Type: string
• Required: true

--b2-key

Application Key.

Properties:

• Config: key
• Env Var: RCLONE_B2_KEY
• Type: string
• Required: true

--b2-hard-delete

Permanently delete files on remote removal, otherwise hide files.

Properties:

• Config: hard_delete
• Env Var: RCLONE_B2_HARD_DELETE
• Type: bool
• Default: false

Advanced options

Here are the Advanced options specific to b2 (Backblaze B2).

--b2-endpoint

Endpoint for the service.

Leave blank normally.

Properties:

• Config: endpoint
• Env Var: RCLONE_B2_ENDPOINT
• Type: string
• Required: false

--b2-test-mode

A flag string for X-Bz-Test-Mode header for debugging.

This is for debugging purposes only. Setting it to one of the strings below will cause b2 to return specific errors:

• "fail_some_uploads"
• "expire_some_account_authorization_tokens"
• "force_cap_exceeded"

These will be set in the "X-Bz-Test-Mode" header which is documented in the b2 integrations checklist.

Properties:

• Config: test_mode
• Env Var: RCLONE_B2_TEST_MODE
• Type: string
• Required: false

--b2-versions

Include old versions in directory listings.

Note that when using this no file write operations are permitted, so you can't upload files or delete them.

Properties:

• Config: versions
• Env Var: RCLONE_B2_VERSIONS
• Type: bool
• Default: false

--b2-version-at

Show file versions as they were at the specified time.

Note that when using this no file write operations are permitted, so you can't upload files or delete them.

Properties:

• Config: version_at
• Env Var: RCLONE_B2_VERSION_AT
• Type: Time
• Default: off

--b2-upload-cutoff

Cutoff for switching to chunked upload.

Files above this size will be uploaded in chunks of "--b2-chunk-size".

This value should be set no larger than 4.657 GiB (== 5 GB).

Properties:

• Config: upload_cutoff
• Env Var: RCLONE_B2_UPLOAD_CUTOFF
• Type: SizeSuffix
• Default: 200Mi

--b2-copy-cutoff

Cutoff for switching to multipart copy.

Any files larger than this that need to be server-side copied will be copied in chunks of this size.

The minimum is 0 and the maximum is 4.6 GiB.