Handling Heavy Write Loads on Red Hat Enterprise Linux

Describes a fix to mitigate resource contention between NFS Clients and the NFS Server on Red Hat Linux.

If you are operating on RHEL and have a heavy NFS write load, you might experience resource contention between the NFS client and the NFS server. This resource contention can cause the NFS server to be unresponsive. To avoid this potential problem, try one of following approaches. These approaches work on all versions of Red Hat (5.x, 6.x and 7.x).

• Edit /etc/sysctl.conf and apply these settings on each NFS server:

  vm.dirty_ratio=10
  vm.dirty_background_ratio=5

  Reboot the server so the changes will take effect. To make the settings take effect immediately, issue the echo command as shown:

  % echo 10 > /proc/sys/vm/dirty_ratio
  % echo 5 > /proc/sys/vm/dirty_background_ratio

• Separate the NFS client from the NFS server so they do not compete for memory on the same system.