SUMMARY: RAID interleave for Solaris Volume Manager

From: Anshuman Kanwar (anshuman_at_expertcity.com)
Date: 06/30/03

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    To: "'sunmanagers@sunmanagers.org'" <sunmanagers@sunmanagers.org>
Date: Mon, 30 Jun 2003 09:41:25 -0700

    Many thanks to Kevin Buterbaugh for an excellent reply and book rec.

    > The "-i" option to metainit is the amount of data that
    > is going to be written per disk before moving to the next
    > disk in the stripe. Therefore, in your RAID 0+1 example,
    > an interlace of 16K with give a 80K chunk. For
    > a 10 disk RAID 5, a 16K interlace gives a 144K chunk.

    > What's really important is matching up the interlace given to
    > metainit with the maxcontig parameter passed to the newfs
    > command when creating a UFS filesystem. The maxcontig should
    > be some integer multiple of the chunk size. So, for example,
    > with your RAID 0+1 stripe, you'd want a maxcontig of 80 or 160
    > or 240 or ... K. HTH
    >
    > If you don't have it, I'd recommend picking up a copy of "System
    > Performance Tuning" (2nd edition) by Musumeci / Loukides, published
    > by O'Reilly. It's got a more detailed explanation of what I've
    > tried to summarize above. HTH...

    Along with this I am using the forcedirectio and noatime flags. Performance
    has increased about 2.5 times.

     

    Thanks again for being a great resource.
    -ansh

    P.S. I'm sorry if I offended the charter of the list by asking a simple
    question. Hichael Morton [mh1272@yahoo.com] seems to have been particularly
    irked. Anyway, I think this was an operational question and the
    documentation was obscure.

    > ==================================
    >
    > Kevin Buterbaugh - Systems Engineer
    > LifeWay - www.lifeway.com

     
    > sunmanagers-bounces@sunmanagers.org wrote on 06/30/2003 12:51:11 AM:
    >
    > > Hi managers,
    > >
    > > I have a basic question regarding -i flag for metainit.
    > > What does this interlace size mean in terms of actual disk
    > > writes ?
    > >
    > > Suppose I have an application that writes in 64KB chunks. I
    > > want Solaris Volume manager (on solaris 9) to match this:
    > > I am trying to dodge multiple writes per application write
    > >
    > > 1) For a RAID 0+1 volume composed of 5+5 disks -i 16k will
    > > give a __kb chunk ?
    > > 2) For a RAID 5 volume of 10 disks how is this stripe size
    > > related to interlace ?
    > >
    > > What should I read to grasp this relationship ? Basically I
    > > am trying to extract as much performance from a A5200 as
    > > possible.
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