Configure NFS Write Performance
The default RPC requests configuration can negatively impact performance and memory. To
avoid performance and memory issues, configure the number of outstanding RPC requests to
the NFS server to be 128. The kernel tunable value
sunrpc.tcp_slot_table_entries
represents the number of simultaneous
Remote Procedure Call (RPC) requests. This tunable's default value is 16. Increasing this
value to 128 may improve write speeds. Use the command sysctl -w
sunrpc.tcp_slot_table_entries=128
to set the value. Add an entry to your
sysctl.conf
file to make the setting persist across reboots.
Perform the following steps as the root user on each NFS client machine:
- ssue the following commands to create the sunrpc.conf file under /etc/modprobe.d with
the recommended configuration. This enables the configuration to persist after a reboot
of the NFS client
machine.
echo "options sunrpc tcp_slot_table_entries=128" >> /etc/modprobe.d/sunrpc.conf echo "options sunrpc tcp_max_slot_table_entries=128" >> /etc/modprobe.d/sunrpc.conf
- Issue the following echo commands. This enables the configuration to take effect after
you remount the NFS client to the NFS
gateway.
echo 128 > /proc/sys/sunrpc/tcp_slot_table_entries echo 128 > /proc/sys/sunrpc/tcp_max_slot_table_entries
- Remount the NFS client to the NFS gateway. Mount the MapR NFS server with a rsize/wsize
of 128K as this significantly cuts down NFS server requests for a given transfer and
improves the overall performance. For example, the following commands unmount and mount
the NFS assuming that the cluster is mounted at
/mapr.
# umount /mapr # mount -o nolock,rsize=131072,wsize=131072 <hostname>:/mapr /mapr
- After the reboot of the node, if the /proc/sys/sunrpc directory is not available or if rpcidmapd is not running, start the rpcidmapd service using the following command: service rpcidmapd start
ERROR nfsserver[38960] fs/nfsd/requesthandle.cc:791 0.0.0.0[0] cannot allocate more OncRpcContexts: [numDropped=2556001] dropping connection from nfsc=10.13.64.225:0