slow performance -- how to diagnose

slow performance -- how to diagnose

[Brian J. Murrell]

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I'm experiencing some slow performance that I have done some initial
diagnosis as per http://nfs.sourceforge.net/nfs-howto/performance.html
but not sure where to go from here.

I have tried both UDP and TCP and in fact UDP performance seems to be
slightly worse.

The connection between a client and the server is gige and seems to
perform pretty close to such using ttcp:

ttcp-t: 819200000 bytes in 7.368 real seconds = 848.299 Mbit/sec +++
ttcp-t: 819200000 bytes in 7.01 real seconds = 891.19 Mbit/sec +++

The first is from client to server and the second server to client.
Both seem reasonable.

The speed of the disk on the server using a simple dd test:

# time dd if=/dev/zero of=file bs=1M count=4000
4000+0 records in
4000+0 records out

real    2m28.756s
user    0m0.024s
sys     0m17.141s

(1024*1024*4000)/148.7/(1024*1024)*8 == 26.899 MB/sec == 215.192Mbit/s

But from an NFS client...

# rsh client5 "(cd $(pwd);time dd if=/dev/zero of=file bs=1M count=1000)"
1000+0 records in
1000+0 records out

real    1m21.036s
user    0m0.006s
sys     0m1.982s

(1024*1024*1000)/81.036/(1024*1024) == 12.340 MB/sec

Any ideas where to look?

b.

-- 
My other computer is your Microsoft Windows server.

Brian J. Murrell

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