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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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