Proxmox 1.9 and Java oom problems

Ever since we upgraded from Proxmox 1.8 to version 1.9 we have had users who have periodically complained about receiving out of memory errors when attempting to start or restart their java apps.

The following two threads contain a little bit more information about the problems people are seeing:

1)Proxmox mailing list thread
2)Openvz mailing list thread

At least one of the threads suggest you allocate a minimum of 2 cpu’s per VM in order to remedy the issue.  We already have 2 cpu’s per VM, so that was not a possible workaround for us.

Another suggestion made by one of the posters was to  revert back to using a previous version of the kernel, or downgrade Proxmox 1.9 to Proxmox 1.8 altogether.

I decided I would try to figure out a work around that did not involving downgrading software versions.

At first I tried to allocate additional memory to the VM’s and that seemed to resolve the issue for a short period of time, however after several days I once again started to hear about out of memory errors with Java.

After checking ‘/proc/user_beancounters’ on several of the VM’s,  I noticed that the failcnt numbers on the  ‘privvmpages’ parameter was increasing steadily over time.

The solution so far for us has been to increase the ‘privvmpages’ parameter (in my case I simply doubled it) to such a level that these errors are no longer incrementing the ‘failcnt’ counter.

If you would like to learn more about the various UBC parameters that can be modified inside openvz you can check out this link.

4 thoughts on “Proxmox 1.9 and Java oom problems

  1. shainmiley Post author

    We do not use KVM for any of our Linux guests…only our virtualized windows machines (and anytime we want to test non Linux based unix machines such as Freebsd).

    I have nothing against it really, however I do like to be able to enter the gusts via the Proxmox hosts using ‘vzctl enter’ and Openvz has such low overhead, there just has not been a reason to do so.

    If I get some free time maybe I will test this out on KVM, however I suspect this is an OpenVZ kernel issue.

  2. jessie

    How were you able to change the privvmpages setting? Is this something you can do on the proxmox web front-end?


  3. shainmiley Post author

    I do not believe you can edit it from the web UI…at least not in the 1.x branch (not sure about 2.x). What you will need to do is edit the configuration file directly. The default location for these is on Proxmox is ‘/etc/vz/conf’. That directory holds the .conf files for all your OpenVZ based vm’s.

    The line in question will look something like this:



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