Date: Wed, 16 Nov 2005 08:19:59 +0100 From: Oliver Lehmann <lehmann@ans-netz.de> To: Mikhail Teterin <mi+mx@aldan.algebra.com> Cc: emoore@freebsd.org, hardware@freebsd.org Subject: Re: very poor performance of LSILogic's SATA 150-6D (RAID5) Message-ID: <20051116081959.54462647.lehmann@ans-netz.de> In-Reply-To: <200511151754.16440.mi%2Bmx@aldan.algebra.com> References: <200511151754.16440.mi%2Bmx@aldan.algebra.com>
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Mikhail Teterin wrote: > Hello! > > We are observing very low performance of the 5- and 6-drive RAID5 array on the > LSILogic. > > For formal comparision we created two logical drives -- a 5-drive RAID5 and a > 1-drive RAID0. (All 6 disks are identical 200Gb Western Digital). > > According to iozone, the 5-drive RAID5 gets from 3 to 8 Mb/s. The 1-drive > RAID0 goes from 20 to 50Mb/s. > > Now, the controller has no battery and thus is not allowed to cache much, but > is the difference really supposed to be so great? It has 5 disks at its > disposal, after all... Hi, before i purchased my 3ware 9500S-4LP I tried an LSI 4port too and I experienced same bad results (which lead me to change it to 3ware). I was running it with 4 WD25000KS. a single disk: 6553600000 bytes transferred in 225.704693 secs (29036171 bytes/sec) (UP) RAID-0: 6553600000 bytes transferred in 204.397157 secs (32063068 bytes/sec) (UP) RAID-5 4194304000 bytes transferred in 146.751626 secs (28580971 bytes/sec) (UP) Notice that all results where takes with an uni-processor (UP) config even my system is SMP. Running the LSI wit SMP was _much_ slower (10MB/sec for RAID-5 iirc). -- Oliver Lehmann http://www.pofo.de/ http://wishlist.ans-netz.de/
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