Messages in this thread | | | Date | Wed, 23 Jun 1999 20:27:05 +0200 | From | Thierry Danis <> | Subject | 2.2.10-ac4 / knfsd 1.4.1 poor parallel reading performance |
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Hello,
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 7+.
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 ?
A+, -- Thierry Danis Poste : 53 53 danis@spmo.sagem.fr
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