Article ID: 119104, created on Dec 11, 2013, last review on Apr 11, 2016

  • Applies to:
  • Operations Automation 5.4
  • Virtuozzo hypervisor


In Parallels Cloud Infrastructure 5.4, containers are getting restored very slowly, in contrast with the backup process. Calculating the time, required for the restoration, manually in the server backend gives the following approximations:

[root@psbm ~]# vzctl exec 827 df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/vzfs             4.8G  1.1G  3.8G  21% /

[root@psbm ~]# time prlctl restore 827
Restore the Vm {0fadaa7d-f88e-46f4-9dda-130620bb74db}
Failed to restore the VM: Failed to restore the virtual machine "827". This virtual machine cannot be restored because it is currently running, suspended, paused, or mounted. Shut down the virtual machine and try to restore it again.

real    0m0.662s
user    0m0.059s
sys     0m0.016s

[root@psbm ~]# time prlctl restore 827
Restore the Vm {0fadaa7d-f88e-46f4-9dda-130620bb74db}
The VM has been restored.

real    15m2.698s
user    0m0.066s
sys     0m0.021s

I.e. a 1GB container is getting backed up within 1 minute and restored within 15 minutes.


The slowness of the container restoration process via prlctl, i.e. Parallels SDK, is known under internal ID PSBM-9872.

The reason why it's getting most visible for containers is because they use VZFS file system, which means that each file inside the container is processed separately by the backup/restore, increasing the time required for the operation. This is not actual for virtual machines and ploop containers, available on Parallels Cloud Server 6.0, as they use HDD images to store the file system inside.


Upgrade to POA 5.5, which requires upgrading all PSBM5 nodes to PCS6.

During the upgrade from PSBM5 to PCS6, make sure containers are converted to ploop format.

There's no way to speed up the restore process for containers within PACI5.4 + PSBM5.

Search Words

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