svn commit: r269788 - head/usr.sbin/nfsd

Rick Macklem rmacklem at
Sun Aug 10 20:05:13 UTC 2014

Author: rmacklem
Date: Sun Aug 10 20:05:13 2014
New Revision: 269788

  Document the use of the vfs.nfsd sysctls that control the size of
  the NFS server's DRC for TCP.
  This is a content change.
  MFC after:	1 week


Modified: head/usr.sbin/nfsd/nfsd.8
--- head/usr.sbin/nfsd/nfsd.8	Sun Aug 10 18:13:50 2014	(r269787)
+++ head/usr.sbin/nfsd/nfsd.8	Sun Aug 10 20:05:13 2014	(r269788)
@@ -28,7 +28,7 @@
 .\"	@(#)nfsd.8	8.4 (Berkeley) 3/29/95
 .\" $FreeBSD$
-.Dd July 18, 2014
+.Dd August 10, 2014
 .Dt NFSD 8
@@ -175,6 +175,24 @@ utility
 would then be used to block nfs-related packets that come in on the outside
+If the server has stopped servicing clients and has generated a console message
+.Dq Li "nfsd server cache flooded..." ,
+the value for vfs.nfsd.tcphighwater needs to be increased.
+This should allow the server to again handle requests without a reboot.
+Also, you may want to consider decreasing the value for
+vfs.nfsd.tcpcachetimeo to several minutes (in seconds) instead of 12 hours
+when this occurs.
+Unfortunately making vfs.nfsd.tcphighwater too large can result in the mbuf
+limit being reached, as indicated by a console message
+.Dq Li "kern.ipc.nmbufs limit reached" .
+If you cannot find values of the above
+.Nm sysctl
+values that work, you can disable the DRC cache for TCP by setting
+vfs.nfsd.cachetcp to 0.
 utility has to be terminated with

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