Since rebooting labstore1004 and 1005 to the new kernel 4.9.0-0.bpo.3-amd64, nfsd processes report these errors on dmesg
[18792.598194] nfsd: last server has exited, flushing export cache [19638.318454] rpc-srv/tcp: nfsd: sent only 390960 when sending 659520 bytes - shutting down socket [20144.705432] rpc-srv/tcp: nfsd: sent only 1006136 when sending 1048640 bytes - shutting down socket [21010.843795] rpc-srv/tcp: nfsd: sent only 387304 when sending 1048640 bytes - shutting down socket [21011.066691] nfsd: last server has exited, flushing export cache [21075.544262] nfsd: last server has exited, flushing export cache [21835.538290] rpc-srv/tcp: nfsd: sent only 256984 when sending 1048640 bytes - shutting down socket [25414.602780] rpc-srv/tcp: nfsd: sent only 57408 when sending 949932 bytes - shutting down socket
@chasemp Adjusted the following settings in /proc/sys/net/core/ to see if it'll help.
sysctl -w net.core.rmem_default=624288
sysctl -w net.core.wmem_default=624288
sysctl -w net.core.netdev_max_backlog=8000
The number of errors have seem to have gone down at-least anecdotally, but we are not sure.