thin_migrate - Man Page

thin_migrate [options] --source-dev {device} --dest-dev {device}
thin_migrate [options] --source-dev {device} --dest-file {file}

thin_migrate copies provisioned data blocks from a thin device to another device or file. It is designed for cloning a read-only snapshot or thin volume within a live thin-pool. A metadata snapshot is required to read the data mappings.

-h,  --help

Print help and exit.

-V,  --version

Print version information and exit.

--source-dev {device}

The input read-only thin device to copy.

--dest-dev {device}

The output device as the copy destination.

--dest-file {file}

The output file as the copy destination.

-q,  --quit

Suppress output messages, return only exit code.

--buffer-size-meg {size}

Specify the size of the data buffers, in megabytes.

Assuming that there's a thin snapshot 'vg/snap' to copy, we must first set the snapshot to read-only:

    $ lvchange vg/snap --permission r

Next, create a metadata snapshot for running thin_migrate:

    $ dmsetup message vg-mythinpool-tpool 0 reserve_metadata_snap

Once the metadata snapshot is created, copy the snapshot into another linear or thin volume. The destination volume must have the same size as the source device.

    $ thin_migrate --src-device /dev/vg/snap --dest-device /dev/vg2/dest

Alternatively, copy the snapshot into a file. thin_migrate can optionally create the destination file if it is not present, or the size of the file will be truncated to match that of the source device.

    $ thin_migrate --src-device /dev/vg/snap --dest-file dest.bin

Finally, release the metadata snapshot after thin_migrate finishes its job:

    $ dmsetup message vg-mythinpool-tpool 0 release_metadata_snap

thin_migrate returns an exit code of 0 for success or 1 for error.

Joe Thornber <ejt@redhat.com>