The idea is simple - backup is "written-once" data. It is written block by block and it is large enough. It would be nice to save storage space and compress it.
These patches add the ability to compress data during backup. This functionality is implemented by means of adding options to the qmp/hmp commands(drive-backup, blockdev-backup). The implementation is quite simple, because the responsibility for data compression imposed on the format driver. Signed-off-by: Pavel Butsykin <[email protected]> Signed-off-by: Denis V. Lunev <[email protected]> CC: Jeff Cody <[email protected]> CC: Markus Armbruster <[email protected]> CC: Eric Blake <[email protected]> CC: John Snow <[email protected]> CC: Stefan Hajnoczi <[email protected]> Changes from v1: - added unittest for backup compression (3) Pavel Butsykin (3): drive-backup: added support for data compression blockdev-backup: added support for data compression qemu-iotests: test backup compression in 055 block/backup.c | 13 ++++++ blockdev.c | 20 ++++++++- hmp-commands.hx | 8 ++-- hmp.c | 3 +- include/block/block_int.h | 1 + qapi/block-core.json | 3 +- qmp-commands.hx | 7 +++- tests/qemu-iotests/055 | 97 +++++++++++++++++++++++++++++++++++++++++++ tests/qemu-iotests/055.out | 4 +- tests/qemu-iotests/iotests.py | 10 ++--- 10 files changed, 150 insertions(+), 16 deletions(-) -- 2.1.4
