[SOLVED] Shortest downtime for lxc container backup

[racitup]

I'm trying to figure out which one of snapshot and suspend I should use for containers to minimise downtime.
Is there a log somewhere that tells me this?

The docs say 'minimal downtime' for suspend, but I would like to compare with snapshot:
https://pve.proxmox.com/pve-docs/chapter-vzdump.html#_backup_modes

 

[liberodark]

Hi,

Is better to use snapshot for best backup integrity.
And that improve speed of backup too.

Best Regards

 

[racitup]

And that improve speed of backup too.

But is there a log that allows me to compare downtime?

 

[fiona]

Hi,
with snapshot mode, the container is just suspended while the snapshot is taken (and only when there's more than one volume attached). For suspend mode, the container will stay suspended until the changed data is copied (which I'd guess will take longer in most cases). If the guest was suspended, there should be a log line like

INFO: guest is online again after XYZ seconds

in the backup log.

 

[racitup]

Thanks for the replies. TLDR: snapshot is the verified answer.

Details:
If you go to /var/log/vzdump on the pve you should have some backup logs for your containers:

root@p1:/var/log/vzdump# grep "backup mode" *
lxc-101.log:2022-07-28 02:12:07 INFO: backup mode: suspend
lxc-150.log:2022-07-28 02:53:08 INFO: backup mode: snapshot
lxc-201.log:2022-07-28 03:14:07 INFO: backup mode: suspend
lxc-202.log:2022-07-27 04:06:03 INFO: backup mode: snapshot
lxc-203.log:2022-07-27 03:43:04 INFO: backup mode: suspend
root@p1:/var/log/vzdump# grep "guest is online" *
lxc-101.log:2022-07-28 02:15:24 INFO: guest is online again after 31 seconds
lxc-201.log:2022-07-28 03:19:16 INFO: guest is online again after 44 seconds
lxc-202.log:2022-07-27 04:06:04 INFO: guest is online again after 1 seconds
lxc-203.log:2022-07-27 03:47:49 INFO: guest is online again after 25 seconds

Points to note:

• 150 only has one disk so doesn't go offline at all in snapshot mode
• 202 is set to snapshot with 2 disks and is only offline for 1 second
• 203 is very similar to 202 and is set to suspend but is offline for 25 seconds