Date: Thu, 9 Dec 2004 12:50:55 -0600 (CST) From: "Jon Noack" <noackjr@alumni.rice.edu> To: "Bill Anderson" <anderson@wks.uts.ohio-state.edu> Cc: freebsd-performance@freebsd.org Subject: Re: 2120S poor performance Message-ID: <17418.69.53.57.66.1102618255.squirrel@69.53.57.66> In-Reply-To: <Pine.GSO.4.33.0412081120520.4974-100000@lennier.uts.ohio-state.edu> References: <Pine.GSO.4.33.0412081120520.4974-100000@lennier.uts.ohio-state.edu>
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Bill Anderson wrote: > I've got a 3x72g RAID5 array with U320 disks on an Adaptec 2120S > controller under Freebsd 4.10. I'm getting about 25MB/s for sequential > reads/writes (e.g. dd if=/dev/aacd0s1b of=/dev/null bs=32k). I've > turned on write caching for the container (container set cache > /write_cache_enable) and turned off the read caching, per previous posts > to this list. I'm going to try setting hw.aac.iosize_max to 96k tonight > to see if that helps. I'm currently using an IDE disk that gets about > 45MB/s, so I can hardly consider it an "upgrade" to switch to a 25MB/s > U320 SCSI system. :/ > > I've also read that the 2120S is slow because of its design. I'm trying > to figure out whether the performance can be increased significantly (I > saw a posting of a linux user getting 37.5MB/s, which although still slow > might be acceptable), or if I'm better off getting a new card. I'm > thinking the latter is the case based on previous postings, but since it > will probably be quite expensive to replace it, I wanted to get some more > data. > > What performance should I be expecting from a decent U320 RAID5 > controller? > > Has anyone gotten a 2120S to perform above 30Mb/s in FreeBSD? > > What's the cheapest controller that still gives reasonable performance? > (If you could give a couple different ones, with their associated > performance (under FreeBSD), or tell me where to find such information, > that would be great) The asr driver is in need of a lot of attention. Still, testing random read/write is much better than testing sequential i/o as most real-world workloads aren't sequential in nature. The raidtest utility (now in ports) does an excellent job with random read/write testing. There are many quality, (relatively) cheap controllers out there, but if you're looking to stick with Adaptec get a 2130S. The 2130S uses the aac driver, which is quite well tuned and maintained by Scott Long. Jon
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