xfs_copy(8) manual page
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xfs_copy - copy the contents of an XFS filesystem
xfs_copy [
-bd ] [ -L log ] source target1 [ target2 ... ]
xfs_copy -V
xfs_copy copies an XFS filesystem to one or more
targets in parallel (see xfs(5)
). The first (source) argument must be the
pathname of the device or file containing the XFS filesystem. The remaining
arguments specify one or more target devices or file names. If the pathnames
specify devices, a copy of the source XFS filesystem is created on each
device. The target can also be the name of a regular file, in which case
an image of the source XFS filesystem is created in that file. If the file
does not exist, xfs_copy creates the file. The length of the resulting file
is equal to the size of the source filesystem. However, if the file is created
on an XFS filesystem, the file consumes roughly the amount of space actually
used in the source filesystem by the filesystem and the XFS log. The space
saving is because xfs_copy seeks over free blocks instead of copying them
and the XFS filesystem supports sparse files efficiently.
xfs_copy should
only be used to copy unmounted filesystems, read-only mounted filesystems,
or frozen filesystems (see xfs_freeze(8)
). Otherwise, the generated filesystem(s)
would be inconsistent or corrupt.
xfs_copy does not alter the source filesystem
in any way. Each new (target) filesystem is identical to the original filesystem
except that new filesystems each have a new unique filesystem identifier
(UUID). Therefore, if both the old and new filesystems will be used as separate
distinct filesystems, xfs_copy or xfsdump(8)
/xfsrestore(8)
should be used
to generate the new filesystem(s) instead of dd(1)
or other programs that
do block-by-block disk copying.
xfs_copy uses synchronous writes to ensure
that write errors are detected.
xfs_copy uses pthreads(7)
to perform simultaneous
parallel writes. xfs_copy creates one additional thread for each target
to be written. All threads die if xfs_copy terminates or aborts.
- -d
- Create a duplicate (true clone) filesystem. This should be done only if
the new filesystem will be used as a replacement for the original filesystem
(such as in the case of disk replacement).
- -b
- The buffered option can be
used to ensure direct IO is not attempted to any of the target files. This
is useful when the filesystem holding the target file does not support
direct IO.
- -L log
- Specifies the location of the log if the default location
of /var/tmp/xfs_copy.log.XXXXXX is not desired.
- -V
- Prints the version number
and exits.
xfs_copy reports errors to both stderr and in more
detailed form to a generated log file whose name is of the form /var/tmp/xfs_copy.log.XXXXXX
or a log file specified by the -L option. If xfs_copy detects a write error
on a target, the copy of that one target is aborted and an error message
is issued to both stderr and the log file, but the rest of the copies continue.
When xfs_copy terminates, all aborted targets are reported to both stderr
and the log file.
If all targets abort or if there is an error reading the
source filesystem, xfs_copy immediately aborts.
xfs_copy returns an exit
code of 0 if all targets are successfully copied and an exit code of 1
if any target fails.
When moving filesystems from one disk to another,
if the original filesystem is significantly smaller than the new filesystem,
and will be made larger, we recommend that mkfs.xfs(8)
and xfsdump(8)
/xfsrestore(8)
be used instead of using xfs_copy and xfs_growfs(8)
. The filesystem layout
resulting from using xfs_copy/xfs_growfs is almost always worse than the
result of using mkfs.xfs/xfsdump/xfsrestore but in the case of small filesystems,
the differences can have a significant performance impact. This is due to
the way xfs_growfs(8)
works, and not due to any shortcoming in xfs_copy
itself.
xfs_copy does not copy XFS filesystems that have a real-time
section or XFS filesystems with external logs. In both cases, xfs_copy aborts
with an error message.
mkfs.xfs(8)
, xfsdump(8)
, xfsrestore(8)
, xfs_freeze(8)
,
xfs_growfs(8)
, xfs(5)
.
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