Article ID: 118277, created on Oct 29, 2013, last review on Jun 17, 2016

  • Applies to:
  • Virtuozzo
  • Virtuozzo containers for Linux
  • Virtuozzo hypervisor


In the system log file /var/log/messages on a hardware node, the following messages can be logged:

kernel: Fatal resource shortage: kmemsize, UB 123.


Such messages are logged if the amount of kernel (unswappable) memory consumed by this environment reached the limit vzlue of kmemsize.

Mainly, kmemsize show the total size of SLAB structures associated with this environment. It directly includes dcachesize and indirectly depends on all num* parameters which are related to the corresponding kernel structures.

This memory is used on processes' start on the stage with linking executable and library files and the limit can be hit in such situations.


  • Increase/remove the limit for kmemsize for the affected container; the barrier value should be either 10-15% less than the limit or removed as well;
  • Decrease the limit and barrier values for dcachesize, keeping these values at 60% or less of the limit value of kmemsize.

NOTE: Setting too low limit for dcachesize can affect performance of the container or be a reason for error similar messages in regards to dcachesize and result in instability of services.

See also

Search Words

Fatal resource shortage: kmemsize, UB

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