bcachefs man page
[Posted July 10, 2019 by corbet]
BCACHEFS(8) System Manager's Manual BCACHEFS(8)
NAME
bcachefs — manage bcachefs filesystems/devices
SYNOPSIS
bcachefs command [options] [arguments]
DESCRIPTION
The bcachefs utility supports the following subcommands, which are docu‐
mented in detail below:
Superblock commands
format Format one or a list of devices with bcachefs data
structures.
show-super Dump superblock information to stdout.
Repair commands
fsck Check an existing filesystem for errors.
Startup/shutdown, assembly of multi device filesystems
assemble Assemble an existing multi device filesystem
incremental Incrementally assemble an existing multi device
filesystem
run Start a partially assembled filesystem.
stop Stop a running filesystem.
Commands for managing a running filesystem
fs usage Show disk usage
Commands for managing devices within a running filesystem
device add Add a new device to an existing filesystem
device remove Remove a device from an existing filesystem
device online Re-add an existing member to a filesystem
device offline Take a device offline, without removing it
device evacuate Migrate data off of a specific device
device set-state Mark a device as failed
device resize Resize filesystem on a device
Commands for managing filesystem data
data rereplicate Rereplicate degraded data
Commands for encryption
unlock Unlock an encrypted filesystem prior to run‐
ning/mounting
set-passphrase Change passphrase on an existing (unmounted) filesys‐
tem
remove-passphrase Remove passphrase on an existing (unmounted) filesys‐
tem
Commands for migration
migrate Migrate an existing filesystem to bcachefs, in place
migrate-superblock Add default superblock, after bcachefs migrate
Commands for debugging
dump Dump filesystem metadata to a qcow2 image
list List filesystem metadata in textual form
Miscellaneous commands
version Display the version of the invoked bcachefs tool
Superblock commands
bcachefs format [options] devices ...
Format one or a list of devices with bcachefs data structures.
You need to do this before you create a volume.
Device specific options must come before corresponding devices,
e.g.
bcachefs format --tier 0 /dev/sdb --tier 1 /dev/sdc
-b, --block=size
block size, in bytes (e.g. 4k)
--btree_node=size
Btree node size, default 256k
--metadata_checksum_type=(none | crc32c | crc64)
Set metadata checksum type (default: crc32c).
--data_checksum_type=(none | crc32c | crc64)
Set data checksum type (default: crc32c).
--compression_type=(none | lz4 | gzip)
Set compression type (default: none).
--data_replicas=number
Number of data replicas
--metadata_replicas=number
Number of metadata replicas
--replicas=number
Sets both data and metadata replicas
--encrypted
Enable whole filesystem encryption (chacha20/poly1305);
passphrase will be prompted for.
--no_passphrase
Don't encrypt master encryption key
--error_action=(continue | remount-ro | panic)
Action to take on filesystem error (default: remount-ro)
-L, --label=label
Create the filesystem with the specified label
-U, --uuid=uuid
Create the filesystem with the specified uuid
-f, --force
Force the filesystem to be created, even if the device
already contains a filesystem.
Device specific options:
--fs_size=size
Create the filesystem using size bytes on the subsequent
device.
--bucket=size
Specifies the bucket size; must be greater than the btree
node size
--discard
Enable discards on subsequent devices
-t, --tier index
Specifies the tier of subsequent devices, where index is
a small integer and a smaller index indicates a faster
tier; tier 0 being the fastest. Currently only two tiers
are supported.
-q, --quiet
Only print errors
bcachefs show-super [options] device
Dump superblock information to stdout.
-f, --fields=fields
List of sections to print
-l, --layout
Print superblock layout
Repair commands
bcachefs fsck [options] devices ...
Check an existing filesystem for errors.
-p Automatic repair (no questions)
-n Don't repair, only check for errors
-y Assume "yes" to all questions
-f Force checking even if filesystem is marked clean
-v Be verbose
Startup/shutdown, assembly of multi device filesystems
bcachefs assemble devices ...
Assemble an existing multi device filesystem.
bcachefs incremental device
Incrementally assemble an existing multi device filesystem.
bcachefs run
Start a partially assembled filesystem.
bcachefs stop filesystem
Stop a running filesystem.
Commands for managing a running filesystem
bcachefs fs usage [options] [filesystem]
Show disk usage.
-h Print human readable sizes.
Commands for managing devices within a running filesystem
bcachefs device add [options] device
Add a device to an existing filesystem.
--fs_size=size
Size of filesystem on device
--bucket=size
Set bucket size
--discard
Enable discards
-t, --tier=number
Higher tier (e.g. 1) indicates slower devices
-f, --force
Use device even if it appears to already be formatted
bcachefs device remove [options] device
Remove a device from a filesystem
-f, --force
Force removal, even if some data couldn't be migrated
--force-metadata
Force removal, even if some metadata couldn't be migrated
bcachefs device online device
Re-add a device to a running filesystem
bcachefs device offline device
Take a device offline, without removing it
-f, --force
Force, if data redundancy will be degraded
bcachefs device evacuate device
Move data off of a given device
bcachefs device set-state [options] device new-state
-f, --force
Force, if data redundancy will be degraded
bcachefs device resize device [size]
Resize filesystem on a device
Commands for managing filesystem data
bcachefs device rereplicate filesystem
Walks existing data in a filesystem, writing additional copies of
any degraded data.
Commands for encryption
bcachefs unlock device
Unlock an encrypted filesystem prior to running/mounting.
bcachefs set-passphrase devices ...
Change passphrase on an existing (unmounted) filesystem.
bcachefs remove-passphrase devices ...
Remove passphrase on an existing (unmounted) filesystem.
Commands for migration
bcachefs migrate [options] device
Migrate an existing filesystem to bcachefs
-f fs Root of filesystem to migrate
--encrypted
Enable whole filesystem encryption (chacha20/poly1305)
--no_passphrase
Don't encrypt master encryption key
-F Force, even if metadata file already exists
bcachefs migrate-superblock [options] device
Create default superblock after migrating
-d device
Device to create superblock for
-o offset
Offset of existing superblock
Commands for debugging
These commands work on offline, unmounted filesystems.
bcachefs dump [options] device
Dump filesystem metadata
-o output
Required flag: Output qcow2 image(s)
-f Force; overwrite when needed
bcachefs list [options] devices ...
List filesystem metadata to stdout
-b (extents | inodes | dirents | xattrs)
Btree to list from
-s inode:offset
Start position to list from
-e inode:offset
End position
-i inode
List keys for a given inode number
-m (keys | formats)
-f Force fsck
-v Verbose mode List mode
Miscellaneous commands
bcachefs version
Display the version of the invoked bcachefs tool
EXIT STATUS
The bcachefs utility exits 0 on success, and >0 if an error occurs.
BSD May 26, 2018 BSD
