proxmox backup (vzdump) parallelism ?

RolandK

Member
Mar 5, 2019
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is there a way to limit backup parallelism/concurrency in a cluster?

i have 5 nodes and when they all have vzdump run in parallel, our nas is heavily saturated and each of the backup "threads" is running slow
 

dylanw

Proxmox Staff Member
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Jul 6, 2020
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RolandK

Member
Mar 5, 2019
162
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49
thanks for the pointers.

limiting bandwidth for vzdump is no option, as limiting backup bandwidth also limits VM io bandwidth, afaik.
 

dylanw

Proxmox Staff Member
Staff member
Jul 6, 2020
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The bandwidth option imposes a limit on disk I/O during the backup, so it's not a general limit on VM disk IO, but it would cause additional slowdown during the backup.
 

RolandK

Member
Mar 5, 2019
162
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yes, and that is the culprit.

it's not such a big deal for me if backup slows down VM disk IO, but slowdown is even growing with the number of cluster nodes and there is nothing you can do against it (without slicing your backup jobs into groups).
 

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