On Tue, Nov 07, 2006 at 01:45:13PM -0800, Andrew Morton wrote:
> On Tue, 07 Nov 2006 14:59:52 -0600
> Dave Kleikamp <shaggy@xxxxxxxxxxxxxxxxxx> wrote:
>
> > On Tue, 2006-11-07 at 11:47 -0800, Andrew Morton wrote:
> > > Why is ext3 slow??
> >
> > Allocation? I don't see anything indicating that Bill is overwriting an
> > existing file, so there is block allocation and journaling overhead. If
> > that's the case, it would be interesting to see how fast ext3 is when
> > overwriting a file. Extents and delayed allocation should improve on
> > this a lot.
Will do.
> Maybe. or perhaps some funniness with RAID aligment.
I neglected to include the relevant RAID/mkfs info here.
device=/dev/sdc2 # ought to have been on a raid stripe boundary
# very close to the start of the array
# XFS:
mkfs.xfs -f -d su=65536,sw=6 -l su=65536 $device
mount -o noatime,attr2,largeio,logbsize=64k $device /mnt
# Ext3: XFS has problems up through 2.6.18-rc5; use slow, but safe, Ext3:
mke2fs -j -J size=400 -E stride=96 $device
mount -o noatime $device /mnt
Also, I ran blockdev --flushbufs and
echo 1 | sudo tee /proc/sys/vm/drop_caches
before each test.
-Bill
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