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Diffstat (limited to 'gitlab/issues_text/target_missing/host_missing/accel_missing/1139')
| -rw-r--r-- | gitlab/issues_text/target_missing/host_missing/accel_missing/1139 | 78 |
1 files changed, 0 insertions, 78 deletions
diff --git a/gitlab/issues_text/target_missing/host_missing/accel_missing/1139 b/gitlab/issues_text/target_missing/host_missing/accel_missing/1139 deleted file mode 100644 index 09b4e7c5b..000000000 --- a/gitlab/issues_text/target_missing/host_missing/accel_missing/1139 +++ /dev/null @@ -1,78 +0,0 @@ -block/nbd.c and drive backup to a remote nbd server -Description of problem: -Good afternoon! - -I trying to copy attached drive content to remote NBD server via drive-backup QMP method. I'he tested two very similar ways but with very different performance. First is a backuping to exported NBD at another server. Second way is a backuping to same server but with connecting to /dev/nbd*. - -Exporting qcow2 via nbd: -``` -(nbd) ~ # qemu-nbd -p 12345 -x backup --cache=none --aio=native --persistent -f qcow2 backup.qcow2 - -(qemu) ~ # qemu-img info nbd://10.0.0.1:12345/backup -image: nbd://10.0.0.1:12345/backup -file format: raw -virtual size: 10 GiB (10737418240 bytes) -disk size: unavailable -``` - -Starting drive backuping via QMP: - -``` -{ - "execute": "drive-backup", - "arguments": { - "device": "disk", - "sync": "full", - "target": "nbd://10.0.0.1:12345/backup", - "mode": "existing" - } -} -``` - -With process starting qemu notifying about warning: - -> warning: The target block device doesn't provide information about the block size and it doesn't have a backing file. The default block size of 65536 bytes is used. If the actual block size of the target exceeds this default, the backup may be unusable - -And backup process is limited by speed around 30MBps, watched by iotop - - -Second way to creating backup - -Exporting qcow2 via nbd: -``` -(nbd) ~ # qemu-nbd -p 12345 -x backup --cache=none --aio=native --persistent -f qcow2 backup.qcow2 -``` - -``` -(qemu) ~ # qemu-img info nbd://10.0.0.1:12345/backup -image: nbd://10.0.0.1:12345/backup -file format: raw -virtual size: 10 GiB (10737418240 bytes) -disk size: unavailable -(qemu) ~ # qemu-nbd -c /dev/nbd0 nbd://10.0.0.1:12345/backup -(qemu) ~ # qemu-img info /dev/nbd0 -image: /dev/nbd0 -file format: raw -virtual size: 10 GiB (10737418240 bytes) -disk size: 0 B -``` - -Starting drive backuping via QMP to local nbd device: - -``` -{ - "execute": "drive-backup", - "arguments": { - "device": "disk", - "sync": "full", - "target": "/dev/nbd0", - "mode": "existing" - } -} -``` - -Backup process started without previous warning, and speed limited around 100MBps (network limit) - -So I have question: how I can get same performance without connection network device to local block nbd device at the qemu host? - -Kind regards |