Throughput problems with NFS

Matthew Dillon dillon at
Sat Oct 11 21:29:13 PDT 2003

:On Sunday, October 12, 2003, at 12:20 AM, Matthew Dillon wrote:
:>     I don't understand.  An unacked segment should not present a 
:> problem.
:>     You may have to make that reserve scale by MTU.
:This happens because Linux hangs onto the ack for the last segment of a
:32K+header send for a while. Then the NFS server will not put anymore
:data in the socket because of an soreserve with a size of 32kB+header, 
:it waits for about 39mS until Linux finally sends the ack for the last

    Ah, ok now I see.  It sounds like soreserve should nominally be 2.5x
    or 3x the NFS io size in order to properly stream requests, or you
    won't be able to fill the wire.

					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>

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