[SOLVED] Migrating Proxmox LXC containers with low downtime

[yarii]

Hellou guys,
I have a big container >500GB whitch I cannot shutdown for a long time.

I use ZFS and my script for migrating is:

I. zfs snapshot zfs-vps2/subvol-105-disk-1@snap1
II. zfs send zfs-vps2/subvol-105-disk-1@snap1 | ssh HOST2 zfs receive zfs-vps1/subvol-105-disk-1
III. pct shutdown 105
IV. zfs snapshot zfs-vps2/subvol-105-disk-1@snap2
V. zfs send -I zfs-vps2/subvol-105-disk-1@snap1 zfs-vps2/subvol-105-disk-1@snap2 | ssh HOST2 zfs receive zfs-vps1/subvol-105-disk-1
VI. ssh HOST2 pct start 105


Steps I-IV goes OK but the last one gets me an error:
cannot receive incremental stream: destination zfs-vps1/subvol-105-disk-1 has been modified

I suspect ZFS automounting for that. How to modify my script to works as I need?
(I copied LXC configurations files earlier).

 

[guletz]

Hi,

I will use pve-zsync insted of custom script. For sure is more reliable; ). Also you can use pve-zsync for the first time using a bandwidth limit that is ok for your lan. Then as the time to migrate is closer, you can repeat pve-zsync, so at the moment of migration(with your CT down) you will transfer a minimum size data over the network.
Using this steps you will have a minimum downtime.

 

[denos]

"zfs receive -F" on step V should take care of your issue.

 

[denos]

Also, if you're running zfs auto snapshot on the receiving end, you need disable snapshots for the receiving filesystem on HOST2 while the first send is in progress:

zfs set com.sun:auto-snapshot=false zfs-vps1/subvol-105-disk-1

After step V, re-enable snapshots on the receiving end:

zfs inherit com.sun:auto-snapshot zfs-vps1/subvol-105-disk-1

 

[yarii]

Also, if you're running zfs auto snapshot on the receiving end, you need disable snapshots for the receiving filesystem on HOST2 while the first send is in progress:

zfs set com.sun:auto-snapshot=false zfs-vps1/subvol-105-disk-1

After step V, re-enable snapshots on the receiving end:

zfs inherit com.sun:auto-snapshot zfs-vps1/subvol-105-disk-1

I did:
zfs set canmount=off zfs-vps1/subvol-105-disk-1

And after V:
zfs set canmount=on zfs-vps1/subvol-105-disk-1

That helped for me. Thanks.