[cciug] Slow writes Linux -> Solaris

From: Lezz Giles (lgiles@avici.com)
Date: Thu Jan 20 2000 - 18:12:59 EST


I know this isn't strictly Clearcase, but somebody on the list might
know
the answer...

I export views from Solaris to Linux (as everybody on the list knows by
now!).
The performance on these exported views, well, basically it sucks. I
did a
little experimentation and found that the performance to any NFS-mounted

filesystem from my Linux box sucks, so the problem is not in Clearcase.
My test setups are:
1) Solaris server -> solaris client with nfs v3
2) Solaris server -> solaris client with nfs v2
3) Solaris server -> linux client with nfs v2
4) Linux server -> linux client with nfs v2

Tests are reading/writing 8 meg of data using dd (reading from
/dev/zero,
writing to /dev/null).

All reads are very fast. I can read 8 meg of data from any server
to any client in a ridiculously short period of time, i.e. well under
a second.

Writing from solaris to solaris, linux to linux, or solaris client
to linux server takes about 8 seconds. I can live with this.

Writing from linux client to solaris server (i.e. the one I really care
about)
takes about 30 to 35 seconds.

I've tried changing the cache size for both read and write caches but,
while I can make things much worse, I can't make things better.

I'm running Red Hat 6.1, but I see the same behaviour with 5.1. Linux
doesn't have an nfs v3 client (or at least my version doesn't).

So has anybody else seen - and solved - this problem?

Thanks in advance,
Lezz Giles

--
Leslie Giles               Software Release Manager           Avici Systems Inc
lgiles@avici.com             Phone: 978.964.2030              Fax: 978.964.2100

"Do not fear the merge"

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