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authorDavid Sterba <dsterba@suse.com>2016-07-14 23:43:38 +0200
committerDavid Sterba <dsterba@suse.com>2016-07-15 00:20:48 +0200
commit4ec42ec46c01030a82c96757d4c39a3956e504d2 (patch)
treef4ec62daafb09fba0bed92b46d819b6f94abec66 /Documentation/btrfs-convert.asciidoc
parente7d6760b1c74f80244b4d5581f9e48e686bb4864 (diff)
btrfs-progs: docs: update btrfs-convert manual page
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'Documentation/btrfs-convert.asciidoc')
-rw-r--r--Documentation/btrfs-convert.asciidoc33
1 files changed, 21 insertions, 12 deletions
diff --git a/Documentation/btrfs-convert.asciidoc b/Documentation/btrfs-convert.asciidoc
index ab3577db..ecc157cd 100644
--- a/Documentation/btrfs-convert.asciidoc
+++ b/Documentation/btrfs-convert.asciidoc
@@ -3,7 +3,7 @@ btrfs-convert(8)
NAME
----
-btrfs-convert - convert from ext2/3/4 filesystem to btrfs
+btrfs-convert - convert from ext2/3/4 filesystem to btrfs in-place
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
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**
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
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**
@@ -45,8 +50,8 @@ filesystem. This will attempt to make file extents more contiguous.
# btrfs filesystem defrag -v -r -f -t 32M /mnt/btrfs
-Verbose recursive defragmentation ('-v', '-r'), flush data per-file ('-f') with target
-extent size 32M ('-t').
+Verbose recursive defragmentation ('-v', '-r'), flush data per-file ('-f') with
+target extent size 32MiB ('-t').
**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
(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
-a soft error leaving the filesystem usable but the block group layout may
-remain unchanged.
+This depends on the free space layout (and fragmentation) and may fail due to
+lack of enough work space. This is a soft error leaving the filesystem usable
+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
OPTIONS
-------
-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
-i|--no-xattr::
ignore xattrs and ACLs of files
@@ -84,17 +90,20 @@ set filesystem label during conversion
-L|--copy-label::
use label from the converted filesystem
-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 '^'.
+Description of the features is in section 'FILESYSTEM FEATURES' of
+`mkfs.btrfs`(8).
+
To see all available features that btrfs-convert supports run:
+
+btrfs-convert -O list-all+
+
-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::
-disable detailed progress and show only the main phases of conversion
+disable progress and show only the main phases of conversion
EXIT STATUS
-----------