From: Jan Kalcic (jandot_at_googlemail.com)
Date: Mon Aug 06 2007 - 22:21:33 CEST
Message-ID: <46B782CD.9080101@googlemail.com> Date: Mon, 06 Aug 2007 22:21:33 +0200 From: Jan Kalcic <jandot@googlemail.com> Subject: Re: [suse-sles-e] Slow direct I/O performance SLES 10 SP1
Andreas Mock wrote:
>> -----Ursprüngliche Nachricht-----
>> Von: suse-sles-e-return-4272-andreas.mock=web.de@suse.com
>>
>> dd oflag=direct if=/dev/zero of=data.out bs=4k count=500000
>>
>>
>
>
> Hi all,
>
> really nobody out there who coud perform this simple
> test with SPLES 10 SP1 on a local filesystem?
>
> dd oflag=direct if=/dev/zero of=data.out bs=4k count=10000
>
> I'm interested in the average throughput and the related hardware.
>
>
> Best regards
> Andreas Mock
>
>
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>
Looking at these outputs it seems to be quite slow also compared with
the outputs of my laptop running openSUSE 10.2. I got to say there is a
software RAID underneath the server. This doesn't help at all. Instead,
device reads timings is rather quick.
# hdparm -t /dev/md1
/dev/md1:
Timing buffered disk reads: 124 MB in 3.01 seconds = 41.26 MB/sec
# dd oflag=direct if=/dev/zero of=data.out bs=4k count=500000
2909+0 records in
2909+0 records out
11915264 bytes (12 MB) copied, 6.6984 seconds, 1.8 MB/s
# dd oflag=direct if=/dev/zero of=data.out bs=4k count=500000
42+0 records in
42+0 records out
172032 bytes (172 kB) copied, 0.832021 seconds, 207 kB/s
# dd oflag=direct if=/dev/zero of=data.out bs=4k count=500000
406+0 records in
406+0 records out
1662976 bytes (1.7 MB) copied, 5.91441 seconds, 281 kB/s
# dd oflag=direct if=/dev/zero of=data.out bs=4k count=500000
2208+0 records in
2208+0 records out
9043968 bytes (9.0 MB) copied, 4.41699 seconds, 2.0 MB/s
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