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    SubjectRe: [Xen-devel] domU is causing misaligned disk writes
    On Tue, Apr 20, 2010 at 11:49:55AM +0300, Pasi Kärkkäinen spake thusly:
    > Are you using filesystems on normal partitions, or LVM in the domU?
    > I'm pretty sure this is a domU partitioning problem.

    Also: What changes in the view of the partitioning between domU and
    dom0? Wouldn't a partitioning error manifest itself in tests in the
    dom0 as well as in the domU?

    BTW: The dd from the last time in my last email finally finished:

    # dd if=/dev/zero of=/dev/xvdg1 bs=4096 count=3000000
    3000000+0 records in
    3000000+0 records out
    12288000000 bytes (12 GB) copied, 734.714 seconds, 16.7 MB/s

    If I run that very same dd as above (the last test in my previous
    email) with the same partition setup again but this time from the
    dom0:

    # dd if=/dev/zero of=/dev/etherd/e6.1 bs=4096 count=3000000
    3000000+0 records in
    3000000+0 records out
    12288000000 bytes (12 GB) copied, 107.352 seconds, 114 MB/s

    # /sbin/sfdisk -d /dev/etherd/e6.1
    # partition table of /dev/etherd/e6.1
    unit: sectors

    /dev/etherd/e6.1p1 : start= 64, size=566226926, Id=83
    /dev/etherd/e6.1p2 : start= 0, size= 0, Id= 0
    /dev/etherd/e6.1p3 : start= 0, size= 0, Id= 0
    /dev/etherd/e6.1p4 : start= 0, size= 0, Id= 0

    Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz
    avgqu-sz await svctm %util
    sda 0.00 17350.80 0.60 275.60 22.40 72540.00
    525.43 97.94 344.01 3.62 100.02
    sdb 0.00 17374.80 1.20 256.00 28.00 74848.00
    582.24 136.20 527.72 3.89 100.02

    72MB/s and 74MB/s per disk in the stripe. Nice. Wish I could get that in a domU!

    --
    Tracy Reed
    http://tracyreed.org
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