Re: freebsd-performance Digest, Vol 4, Issue 7

From: Eric Anderson (anderson_at_centtech.com)
Date: 06/18/03

  • Next message: Jin Guojun [DSD]: "Re: freebsd-performance Digest, Vol 4, Issue 7" 
    Date: Wed, 18 Jun 2003 15:44:14 -0500
To: "Jin Guojun [DSD]" <j_guojun@lbl.gov>

    Jin Guojun [DSD] wrote:
    > Eric Anderson wrote:
    >
    >
    >>>Very minimum.
    >>>It was slow on SCSI bus , but I do not have time to diagnose,
    >>>which can be very time consuming.
    >>
    >>My tests have shown that a GOOD hardware RAID5 controller can really
    >>help you out when it's being slammed (specially over NFS) - I use Dell
    >>PERC/2 and PERC/3 controllers (rebranded AMI RAID boards). They run
    >>like champs, and I get 40MB/s sustained xfers..
    >
    >
    > What did you mean sustained xfers ? -- in and out, or just read out.

    sustained writes (not burst transfers) and sustained reads.. With
    hardware RAID's that have cache memory on them (as the PERC's do - mine
    has 128mb), you can get huge burst speeds (all in memory, so it makes
    sense). If you have a machine that is writing small files constantly,
    the cache can significantly help. However, putting a lot of extra
    memory in the server running a software RAID can do this with similar
    results. I always suggest piling on the RAM for servers..

    Eric 

    -- 
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Eric Anderson	   Systems Administrator      Centaur Technology
Attitudes are contagious, is yours worth catching?
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