Re: IDE-RAID Drive Performance

From: Bob (recbo_at_nishanet.com)
Date: 01/02/04

  • Next message: Jeff Chua: "GetASF failed on DVD authentication"
    Date:	Fri, 02 Jan 2004 03:19:10 -0500
    To: kernel list <linux-kernel@vger.kernel.org>
    
    

    Nuno Alexandre wrote:

    >On Tue, 30 Dec 2003 11:44:01 +0100
    >Mr(s): Nicklas Bondesson wrote:
    >
    >
    >
    >>Hi!
    >>
    >>I think i'm getting really bad values from my disks. It's two Western
    >>Digital WD800JB-00DUA3 (Special Edition 8 MB cache) disks connected to a
    >>Promise TX2000 (PDC20271) card (RAID1 using ataraid under Linux 2.4.23).
    >>
    >>The disks are setup with hdparm at boot time:
    >>
    >>/sbin/hdparm -X69 -d1 -u1 -m16 -c3 /dev/hda
    >>/sbin/hdparm -X69 -d1 -u1 -m16 -c3 /dev/hdc
    >>
    >>When running hdparm -tT I get the following:
    >>
    >>/dev/hda:
    >> Timing buffer-cache reads: 128 MB in 1.13 seconds =113.27 MB/sec
    >> Timing buffered disk reads: 64 MB in 2.46 seconds = 26.02 MB/sec
    >>
    >>/dev/hdc:
    >> Timing buffer-cache reads: 128 MB in 1.13 seconds =113.27 MB/sec
    >> Timing buffered disk reads: 64 MB in 2.47 seconds = 25.91 MB/sec
    >>
    >>Are these normal values? I don't think so. Please advise.
    >>
    >>/Nicke
    >>
    >>
    >
    >Hi.
    >This is what i get with a Maxtor 6Y120L0 (2MB cache):
    >
    >/dev/hda:
    > Timing buffer-cache reads: 1320 MB in 2.00 seconds = 659.44 MB/sec
    > Timing buffered disk reads: 140 MB in 3.02 seconds = 46.40 MB/sec
    >
    >Using:
    >-d1 -u1 -m16 -c3 -W1 -A1 -k1 -X70 -a 8192
    >
    >I'm not using raid, its a single disk connected to IDE1 on the motherboard.
    >
    >Maybe you can try those parameters and see if it helps :)
    >
    >
    I have two promise cards and four Maxtor
    DiamondMax Plus9 60G with 8MB cache each
    hdparm -d1 -u1 -m16 -c1 -W1 -A1 -k1 -X70 -a 8192

    and my raid0 is software, linux, not the promise chip's raid

    on each drive I see 900 MB/s 47.2 MB/s
    and on /dev/md/2 /tmp with four drives
    four partitions I see 900 MB/s 94 MB/s

    that's with 64k raid chunk, reiser 4096b blocks

    Linux says 2048k raid chunk would minimize
    seek time for better real world performance. It
    doesn't work better with hdparm -tT but that's not
    realworld. My version of reiserfs doesn't allow
    changing the block size.

    -Bob D
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/


  • Next message: Jeff Chua: "GetASF failed on DVD authentication"

    Relevant Pages

    • Re: Software RAID5 with 2.6.0-test
      ... Seagate disks on a Highpoint controller. ... only measures 25 MB/s. ... read speeds at least equal to the underlying disks. ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • Re: Where is the performance bottleneck?
      ... >> To further reduce dirty memory in the system, ... > it it was 24.958557 MB/s on average per disk. ... for the dd write tests an average of 24.559491 MB/s (8 disks in parallel) ... send the line "unsubscribe linux-kernel" in ...
      (Linux-Kernel)
    • Re: Adaptect raid performance with FreeBSD
      ... > giving a theoretical data transfer speed of 80 MB/s. ... > The disks are maxtor atlas 10K4, ... there is only setting to enable bus mastering ...
      (freebsd-stable)
    • Re: Where is the performance bottleneck?
      ... 240 MB/s per channel. ... you're obviously saturating something already with 2 disks. ... the block-out is clearly distorted by buffer-cache, ...
      (Linux-Kernel)