[pve-devel] KVM Live Backup performance

Eric Blevins eric at netwalk.com
Mon Nov 25 16:00:29 CET 2013


>> I have not tested writes yet and doubt I will have time to get to that this week.
> To show drawbacks of LVM snapshots, you can use something like:
>
> # dd if=/dev/urandom of=tmp.raw bs=1M
>
> inside the VM during backup.
>
> LVM snapshot will most likely run full, and is very slow:
This is not the problem that some of us are having.
It is agreed that live backup is better at performing the backup operation.

The reduced performance of IO in the VM during a live backup is the 
problem. This degraded performance is causing real world problems like 
corrupted filesystems, failed services and reduced performance.

I would rather use a backup system that is slower and might fail from a 
full snapshot than one that is causing failures in the guests.




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