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Re: [ccp4bb]: NFS Performance



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Hi Martin

I would check the following things:

1) is the CCP4_SCR variable set to a LOCAL disk (setting this to a
   directory on a NETWORK disk dramatically reduces performance)

2) are you sure both NFS server and client are with network cards that
   actually run at 100 MBit (check by looking at LEDs on the back of the
   network cards and the switches the machines are on.

3) if, logged into the linux machine, you put and get a large file via
   ftp from the SGI are you indeed getting significantly more than
   1000 Kbytes/sec ?

4) are you using NFS version 2 or 3? Switching this might also help.

hope this helps

Daan


On Tue, 16 Apr 2002, Martin Singleton wrote:

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> ***          CCP4 home page http://www.ccp4.ac.uk         ***
>
>
> Dear All
>
> We have recently started using Linux (RedHat 7.2) machines in our SGI
> based network.
> All of our user accounts are held on an NFS exported filesystem from an
> SGI server. This filesystem is mounted on the Linux machine as well as the
> other SGIs. Linux sees the filesystem fine, but there appears to be a
> major performance problem when certain CCP4 programs as well as SOLVE on
> the Linux box requires access to this filesystem. The problem seems to
> occur during read/writes of large binary files, which cause programs to
> slow to a crawl, in some cases increasing the run time by two orders of
> magnitude. I have noticed that the programs processor usage often drops to
> < 1% when this occurs and the machine rapidly runs out of memory (1GB
> real!) If the same process is run on the local (ext3) disc only, or on the
> SGI machines, there are no such problems. Obviously the problem lies with
> the Linux-IRIX disc cross-mounting, but so far I have not been able to see
> where, and the documented NFS options do not seem to help. Has anyone else
> noticed this problem, or suggest any solutions ?
>
> Regards
>
> Martin Singleton
> Cancer Research UK
> Clare Hall Laboratories,
> South Mimms,
> Herts EN6 3LD
> martin.singleton@cancer.org.uk
>
>
>
>


##############################################################################

Dr. Daan van Aalten                    Wellcome Trust RCD Fellow
Wellcome Trust Biocentre, Dow Street   TEL: ++ 44 1382 344979
Div. of Biol.Chem. & Mol.Microbiology  FAX: ++ 44 1382 345764
School of Life Sciences                E-mail: dava@davapc1.bioch.dundee.ac.uk
Univ. of Dundee, Dundee DD1 5EH, UK    WWW: http://davapc1.bioch.dundee.ac.uk

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