btrfs-progs/Documentation/btrfs-image.rst

btrfs-image(8)
==============

SYNOPSIS
--------
**btrfs-image** [options] <source> <target>

DESCRIPTION
-----------

:command:`btrfs-image` is used to create an image of a btrfs filesystem.
All data will be zeroed, but metadata and the like is preserved.
Mainly used for debugging purposes.

In the dump mode, source is the btrfs device/file and target is the output
file (use *-* for stdout).

In the restore mode (option *-r*), source is the dumped image and target is the btrfs device/file.

OPTIONS
-------

-r
        Restore metadump image. By default, this fixes super's chunk tree, by
        using 1 stripe pointing to primary device, so that file system can be
        restored by running tree log reply if possible. To restore without
        changing number of stripes in chunk tree check *-o* option.

-c <value>
        Compression level (0 ~ 9).

-t <value>
        Number of threads (1 ~ 32) to be used to process the image dump or restore.

-o
        Use the old restore method, this does not fixup the chunk tree so the restored
        file system will not be able to be mounted.

-s
        Sanitize the file names when generating the image.  Not recommended as
        this would introduce new file name hash mismatches, thus if your
        problem involves subvolume tress, it can even mask existing problems.
        Furthermore kernels can not do proper path resolution due to the
        introduced hash mismatches.

        One *-s* means just generate random garbage, which means that the
        directory hash won't match its file names.  Using two *-s* will
        calculate a collision for the file name so that the hashes match, and
        if it can't calculate a collision then it will just generate garbage.
        The collision calculator is very time and CPU intensive.

-w
        Walk all the trees manually and copy any blocks that are referenced. Use this
        option if your extent tree is corrupted to make sure that all of the metadata is
        captured.

-m
        Restore for multiple devices, more than 1 device should be provided.

EXIT STATUS
-----------

**btrfs-image** will return 0 if no error happened.
If any problems happened, 1 will be returned.

SEE ALSO
--------

:doc:`mkfs.btrfs`