amd64/112528: NFS over TCP under load hangs with "impossible
fabian at wenks.ch
Wed May 9 16:20:47 UTC 2007
>>Synopsis: NFS over TCP under load hangs with "impossible packet length"
Just a side note to NFS with Gbit Ethernet:
The manpage of nfs(5) on Suse Linux has an interesting section
about "Using NFS over UDP on high-speed links such as Gigabit can
cause silent data corruption.". See the "WARNINGS" Section at the
end of the manpage  for more.
If the clients are Linux with Kernel 2.4.x then NFS over TCP is
very slow compared to UDP. With Linux Kernel 2.6.x the performance
of NFS over TCP is the same as with NFS over UDP. Do not forget to
set /proc/sys/net/ipv4/ipfrag_time to 2 on Linux clients when
using NFS over UDP on Gbit Ethernet.
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