Backup a KVM machine without disks.

[rmoglia]

I want make a DUMP with VM configurations without disks.
Disks is verry BIG so i will use rsync to copy disk across network to a target machine.
For openvz i exclude bigdata directories todo a fast dump process and sync
big data directories.

After that i need ask for a ip block migration because the machine
is on another network.

Any idea to minimize my downtime.

Thanks.

 

[m.ardito]

you could mark your vm "big" disk with "no backup" (see vm hw tab)
=> but pve backup needs at least 1 disk to backup.
so you could easily just add another minimal empty disk - 1GB - without flagging is as "no backup" (default) so the backup should work and be fast (disk has nothing inside)
your big disk will be ignored, as you wish. Never tried though. If with a totally empty disk vzdump complains, add some fake data in the dummy disk, and retry.

Marco

 

[rmoglia]

I use this method now move a big disk and replace by small file on backup time.
But i can do hot backup with machine turned on.

 

[m.ardito]

sorry, not so clear to me.

1) how big is the disk you need to backup with rsync? which kind of data makes the need for it to be so big?
2) which kind of sw/hw/network is behind your best backup storage? (if is a local storage, this are your pve specs, if is a network share, this is youe nas specs + network)
3) which pve backup method you would use ideally (stop, suspend, snapshot)?
4) if you ever tried pve backup, which backup times you got and with which method?
5) why can't you use a 2 disk setup in pve vm (1 small for os, 1 big for big data) and set the big one as "no backup", and then use another (faster) backup method to backup big data (eg: backuppc, rsync, or others classic backup softwares)?

Marco

 

[rmoglia]

1) how big is the disk you need to backup with rsync? which kind of data makes the need for it to be so big?

Between 100-200 GB

2) which kind of sw/hw/network is behind your best backup storage? (if is a local storage, this are your pve specs, if is a network share, this is youe nas specs + network)

On a remote machine no iSCSI, NFS or another storage method.

3) which pve backup method you would use ideally (stop, suspend, snapshot)?

snapshot for openvz and stop for KVM

4) if you ever tried pve backup, which backup times you got and with which method?

No only dumps on console direct on shell.

5) why can't you use a 2 disk setup in pve vm (1 small for os, 1 big for big data) and set the big one as "no backup", and then use another (faster) backup method to backup big data (eg: backuppc, or others classic backup softwares)?

Yes windows 2003 machines backuped data with syncback but now i´m migrating VM between 2 hosts.

 

[m.ardito]

Yes windows 2003 machines backuped data with syncback but now i´m migrating VM between 2 hosts.

I'm still not sure to understand, but it could easily be me if I got it:

you kvm vm with VMID config is on /etc/pve/nodes/pve2/qemu-server/100.conf, so if you have rsynced the big disk to the other node, you can simply copy 100.conf to the remote node.

if the big disk is fully rsynced, the new vm can simply start using it (stop the old vm first)
to avoid rsync, if you had a networked share (eg. a nas) seen by the two networks, you could simply stop the first vm, and start the new one: both would see the same disk from the network.

Marco