btrfs-progs: docs: update btrfs-convert manual page

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2016-07-14 23:43:38 +02:00
parent e7d6760b1c
commit 4ec42ec46c

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@ -3,7 +3,7 @@ btrfs-convert(8)
NAME NAME
---- ----
btrfs-convert - convert from ext2/3/4 filesystem to btrfs btrfs-convert - convert from ext2/3/4 filesystem to btrfs in-place
SYNOPSIS SYNOPSIS
-------- --------
@ -28,6 +28,11 @@ steps to transform the btrfs filesystem to a more compact layout. The
conversion inherits the original data block fragmentation and the metadata conversion inherits the original data block fragmentation and the metadata
blocks are bound to the original free space layout. blocks are bound to the original free space layout.
Due to different constraints, it's possible to convert only filesystem that
have supported data block size (ie. the same that would be valid for
'mkfs.btrfs'). This is typically the system page size (4KiB on x86_64
machines).
**REMOVE THE ORIGINAL FILESYSTEM METADATA** **REMOVE THE ORIGINAL FILESYSTEM METADATA**
By removing the 'ext2_saved' subvolume, all metadata of the original filesystem By removing the 'ext2_saved' subvolume, all metadata of the original filesystem
@ -36,7 +41,7 @@ will be removed:
# btrfs subvolume delete /mnt/ext2_saved # btrfs subvolume delete /mnt/ext2_saved
At this point it's not possible to do rollback. The filesystem is usable but may At this point it's not possible to do rollback. The filesystem is usable but may
be impacted by the fragmentation. be impacted by the fragmentation inherited from the original filesystem.
**MAKE FILE DATA MORE CONTIGUOUS** **MAKE FILE DATA MORE CONTIGUOUS**
@ -45,8 +50,8 @@ filesystem. This will attempt to make file extents more contiguous.
# btrfs filesystem defrag -v -r -f -t 32M /mnt/btrfs # btrfs filesystem defrag -v -r -f -t 32M /mnt/btrfs
Verbose recursive defragmentation ('-v', '-r'), flush data per-file ('-f') with target Verbose recursive defragmentation ('-v', '-r'), flush data per-file ('-f') with
extent size 32M ('-t'). target extent size 32MiB ('-t').
**ATTEMPT TO MAKE BTRFS METADATA MORE COMPACT** **ATTEMPT TO MAKE BTRFS METADATA MORE COMPACT**
@ -54,18 +59,19 @@ Optional but recommended step.
The metadata block groups after conversion may be smaller than the default size The metadata block groups after conversion may be smaller than the default size
(256MiB or 1GiB). Running a balance will attempt to merge the block groups. (256MiB or 1GiB). Running a balance will attempt to merge the block groups.
This depends on the free space layout (and fragmentation) and may fail. This is This depends on the free space layout (and fragmentation) and may fail due to
a soft error leaving the filesystem usable but the block group layout may lack of enough work space. This is a soft error leaving the filesystem usable
remain unchanged. but the block group layout may remain unchanged.
Note that balance operation takes a lot of time. Note that balance operation takes a lot of time, please see also
`btrfs-balance`(8).
# btrfs balance start -m /mnt/btrfs # btrfs balance start -m /mnt/btrfs
OPTIONS OPTIONS
------- -------
-d|--no-datasum:: -d|--no-datasum::
disable data checksum calculations and set NODATASUM file flag, this can speed disable data checksum calculations and set the NODATASUM file flag, this can speed
up the conversion up the conversion
-i|--no-xattr:: -i|--no-xattr::
ignore xattrs and ACLs of files ignore xattrs and ACLs of files
@ -84,17 +90,20 @@ set filesystem label during conversion
-L|--copy-label:: -L|--copy-label::
use label from the converted filesystem use label from the converted filesystem
-O|--features <feature1>[,<feature2>...]:: -O|--features <feature1>[,<feature2>...]::
A list of filesystem features turned on at btrfs-convert time. Not all features A list of filesystem features turned on at conversion time. Not all features
are supported by old kernels. To disable a feature, prefix it with '^'. are supported by old kernels. To disable a feature, prefix it with '^'.
Description of the features is in section 'FILESYSTEM FEATURES' of
`mkfs.btrfs`(8).
+ +
To see all available features that btrfs-convert supports run: To see all available features that btrfs-convert supports run:
+ +
+btrfs-convert -O list-all+ +btrfs-convert -O list-all+
+ +
-p|--progress:: -p|--progress::
show progress of conversion, on by default show progress of conversion (a heartbeat indicator and number of inodes
processed), on by default
--no-progress:: --no-progress::
disable detailed progress and show only the main phases of conversion disable progress and show only the main phases of conversion
EXIT STATUS EXIT STATUS
----------- -----------