Date: Wed, 18 Jun 2003 15:44:14 -0500 From: Eric Anderson <anderson@centtech.com> To: "Jin Guojun [DSD]" <j_guojun@lbl.gov> Cc: freebsd-performance@freebsd.org Subject: Re: freebsd-performance Digest, Vol 4, Issue 7 Message-ID: <3EF0CF1E.9020901@centtech.com> References: <20030614190033.7F0DE37B407@hub.freebsd.org> <20030615091254.M85497@bluhayz.org> <3EF0B507.2B1B6FDF@lbl.gov> <3EF0C5FA.302@centtech.com> <3EF0CADD.B096A242@lbl.gov>
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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 -- ------------------------------------------------------------------ Eric Anderson Systems Administrator Centaur Technology Attitudes are contagious, is yours worth catching? ------------------------------------------------------------------
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