Question about Backup on different Disk.


Sep 21, 2018
Hi all, and nice to meet you.
Sorry if the following has already been discussed, i wasn't able to find relevnt information about it.

I'd like to perform automatic backups of my VMs (KVM).
Due to space reasons, i plain to keep the backups on a separate - ext4 mounted - drive, and i'm trying to -understand what's the best option for me.
* The ext4 drive is slow, compared to the main raid array

I'd like to avoid shutting down VMs, so my options are:
1) Suspend ?
2) Snapshot ?

While it performs backup, the vm proces seems to be freezed.
As soon as the backup ends, it is resumed and everything continue to work, good.
Anyway, when i restore that backup, the VM starts from the beginning (full boot process), instead of "resuming" from a suspended state.
Plus, the machine performs a filesystem check, as it was powered down badly.
Is that intended to work that way, or am i doing something wrong?

I did not tried that extensively, I'm concerned by the fact that i'm using another Disk to keep my backups (or snapshots), so the snapshotting process is taking some time (minutes), to complete.
And while the snapshot process is performed, the VM continues to run.
What if the blocks on the disk are changed while the snapshot is created? I really fear filesystem corruption.
Wiki says:
"This mode provides the lowest operation downtime, at the cost of a small inconstancy risk."
...but i'm not sure it considers snapshotting on a different drive.
Probably what i'd need is some sort of Suspend+Snapshot+Resume?

Thanks for reading!
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