[Beowulf] NFS & Scaling issues
asingh at ideeinc.com
Tue Apr 3 13:39:32 PDT 2007
We are running a cluster of 180 diskless compute nodes. 60 of them have
32 bit AMD Semptron processors and rest are dual core AMD Athelon 64
bit processors. 32 bit machines have 10/100 mbps and rest have gigabit
ethernet cards. We have four file servers, each hosting around 3.5TB on
SATA drives connected to 3Ware RAID controller cards configured on RAID
10 array. These file servers are exporting the drives through NFS. Each
file server is running 265 daemons for nfsd.
The file servers are mainly hosting large number of small files ranging
from 256KB to 2 MB. The compute nodes are primarily doing a search
through these files, so there is lot's of reading and some writing to
the file servers.
Recently we started noticing very high (70-90%) wait states on the file
servers when compute nodes. We have tried to optimize the NFS through
increasing the number of daemons and the rsize and wsize but to no avail.
Can someone point us in the right direction as to how we should be
trying to troubleshoot this problem.
PS: All the nodes are running SuSE 10.0 and servers are running SuSE10.0
and 10.1 and all the drives are formatted with reiserfs.
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