kernel: nfsd: too many open TCP sockets, consider increasing the number of threads
This document (7010903) is provided subject to the disclaimer at the end of this document.
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server 11
Boosting the number of threads (even dramatically) is not likely to cause any negative side effects unless the machine in question is already struggling to keep up with workload even before any NFS work is introduced. Therefore, it is safe to be generous with this setting.
When putting any NFS Server into enterprise production, it would be good to boost this setting to at least 16. This will give it more room for load than the default of 4.
Then, if NFS client performance problems are seen or suspected, experiment with values in the range of 32 to 128. Something within this range will usually prove to be both safe and sufficient for busy enterprise servers. In some cases of extreme load, going even higher than 128 may be needed.
After making a change, the nfs server daemon can be restarted with:
ON SLES 12 or 15:
systemctl restart nfsserver
On SLES 10 or 11:
The message is given when connections to the NFS server's port 2049 are greater than:
[(number of threads + 3) * 20]
For example, at the default of 4, the message will be logged if connections to port 2049 exceed 140. However, there could be many connection present with each doing very little work, or there could fewer connections each doing a tremendous amount of work. Performance problems may exist even without the warning being logged.
However, even before reaching the number of connections which the formula indicates, performance problems related to the number of threads will often exist. Therefore, the recommendations given in the 'Resolution" section above are typically higher than would be indicated by the formula.
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- Document ID:7010903
- Creation Date: 10-Oct-2012
- Modified Date:01-Oct-2021
- SUSE Linux Enterprise Server
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