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Subject2.2.10-ac4 / knfsd 1.4.1 poor parallel reading performance


I am running 2.2.10-ac4 + knfsd 1.4.1, and, as for the previous
versions, the server behaves strangely very badly when concurrent
readers are accessing the NFS exported partitions.

Using iozone, I can achieve roughly 6 Mo/s with one reader.
Using many readers (from 2 readers upwards), reading rate
drops to 1,5 Mo/s cumulated. For example, with 3 readers, each
of them reads at 500 Ko/s, and the load of the server climbs to

Using many iozones locally on the server shows that the cumulated
reading rate is independant (or just with little performance loss)
to the rate obtained with one reader (ie, ~ 10 Mo/s).

So, the problem seems to be the simultaneous NFS accesses (maybe combined
with simultaneous disk accesses).

Any idea ?

Thierry Danis
Poste : 53 53

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