Re: 2120S poor performance

From: Jon Noack (noackjr_at_alumni.rice.edu)
Date: 12/09/04

  • Next message: Steven Hartland: "Re: 2120S poor performance" 
    Date: Thu, 9 Dec 2004 12:50:55 -0600 (CST)
To: "Bill Anderson" <anderson@wks.uts.ohio-state.edu>

    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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  • Next message: Steven Hartland: "Re: 2120S poor performance"