Re: Very low disk performance on 5.x

From: Petri Helenius (pete_at_he.iki.fi)
Date: 05/02/05

  • Next message: Poul-Henning Kamp: "Re: Very low disk performance on 5.x" 
    Date: Mon, 02 May 2005 16:23:23 +0300
To: Poul-Henning Kamp <phk@phk.freebsd.dk>

    Poul-Henning Kamp wrote:

    >In message <427626DC.5030702@centtech.com>, Eric Anderson writes:
    >
    >
    >
    >>Don't mean to be terse here, but I'm talking about the same test done an
    >>two different RAID5 configurations, with different disks, and not just
    >>me - other users in this very thread see the same issue..
    >>
    >>
    >
    >Uhm, if you are using RAID5 and your requests are not aligned and
    >sized after the RAID5 you should *expect* read performance to be poor.
    >
    >If you your request ends up accessing two different blocks even just
    >once per stripe, this totally kills performance.
    >
    >
    >
    >
    My tests were using RAID10 and just striping. (RAID0 might be the right
    name for it)

    Pete

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