PE 1800 PERC4/SC write performance

Greg Gilmour greg at ipr0n.com
Mon Apr 3 16:38:49 CDT 2006


On Mon, Apr 03, 2006 at 06:49:38PM +0200, Tino Schwarze wrote:
> On Mon, Apr 03, 2006 at 11:35:54AM -0500, Greg Gilmour wrote:
> > =============
> > ############################
> > # PowerEdge 1800, PERC4/SC #
> > ############################
> > 
> > :~# time dd if=/dev/zero of=testfile bs=1024k count=1024
> > 1024+0 records in
> > 1024+0 records out
> > 1073741824 bytes transferred in 62.297558 seconds (17235697 bytes/sec)
> 
> 17 MB/s is pretty poor, yes.
> 
> > :~# dd if=testfile of=/dev/null bs=1024k count=1024
> > real    1m2.314s
> > user    0m0.010s
> > sys     0m3.890s
> > 1024+0 records in
> > 1024+0 records out
> > 1073741824 bytes transferred in 0.532994 seconds (2014547399 bytes/sec)
> 
> I suppose, you actually benchmarked your RAM, since the testfile you
> created above was still in cache. Try bonnie for real HD benchmarking
> and use file sizes much larger than your RAM.
> 
> > time rm -f testfile
> > real    3m25.088s
> > user    0m0.000s
> > sys     0m0.370s
> > 
> > Read speeds are excellent, but it took over 3 minutes to remove a 1 GB
> > file (!).  By comparison, I ran the same tests on a PE SC430 I have for
> > personal use running software RAID-1:
> > 
> > #############################
> > # PE SC430, software RAID-1 #
> > #############################
> > 
> > :~$ time dd if=/dev/zero of=testfile bs=1024k count=1024;
> > 1024+0 records in
> > 1024+0 records out
> > 1073741824 bytes transferred in 15.655173 seconds (68587031 bytes/sec)
> > 
> > :~$ dd if=testfile of=/dev/null bs=1024k count=1024
> > real    0m15.656s
> > user    0m0.000s
> > sys     0m3.704s
> > 1024+0 records in
> > 1024+0 records out
> > 1073741824 bytes transferred in 22.524258 seconds (47670464 bytes/sec)
> 
> These numbers look real.
> 
> I've got no idea on how to improve the write speed, though.
> 
> Bye, Tino.

I ran bonnie++ and here are the results:

http://www.g-3.org/bonnie.txt

My next thoughts are to disable the write-cache on the PERC4/SC
(hopefully without having to re-create the logical drive) and probably
also repartition/reinstall and have a OS-specific partition and a data
partition where I used a different file system (like ReiserFS or XFS).

Suggestions welcome.


Thanks again.

--
~~~~~~~~
- greg
"hrmmm - a Beowulf cluster of Dreamcasts and PS2s..."
                        -Slashdot.org post



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