What are the problems caused by very large dentry slab? and How to use negative-dentry-limit sysctl parameter?

Solution Verified - Updated -


  • Temporary unresponsiveness of container runtime.
  • Performance issues of processes, commands and/or systemcalls working with files or directories.
  • Slowness or even softlockups during unmount, reclaim and/or lookup routines.
  • Large negative dentries can cause system unresponsiveness during systemd reloads
  • OpenShift logs PLEG is not healty and NodeNotReady errors.
  • Use of the curl command in OpenShift liveness and/or readiness probes bloats the dentry cache.

  • What is the negative-dentry-limit kernel parameter?

  • Need guidance to set the negative-dentry-limit kernel parameter.


  • Red Hat Enterprise Linux 7
  • OpenShift Container Platform
  • SAP environments running on RHEL
  • crio or docker container runtime

Note: Issues arising from overgrown dentry slab (namely due to negative dentries) can affect any Red Hat products or workloads utilizing RHEL kernel underneath. (i.e. not necessarily just RHOCP)

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