Date: Sat, 19 Dec 1998 07:22:29 +0000 ( ) From: Patrick Mau <patrick@oscar.prima.de> To: Linux Kernel <linux-kernel@vger.rutgers.edu>, AIC7xxx-List <aic7xxx@FreeBSD.ORG> Subject: Please comment on SCSI performance Message-ID: <Pine.LNX.4.00.9812190649240.696-100000@oscar.prima.de>
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Dear SCSI users, my machine is a P133 with a plain 2.1.131 kernel. I was testing RAID0 performance of two of my drives with time dd if=/dev/sd?? of=/dev/null bs=1024k count=128 to compare them to the speeds of the single drives. To my surprise all my drives are showing the same slow performance. All tests are repeated serveral times on an idle system. The SCSI host adaptor is an Adaptec 3940 with aic driver version 5.1.4 The drives are: Vendor: QUANTUM Model: LIGHTNING 730S Rev: 241E Vendor: IBM Model: DORS-32160 Rev: WA6A Vendor: IBM Model: DPES-31080 Rev: S31Q The timings are: sda1: real 0m36.719s user 0m0.010s sys 0m6.190s (3.48 MB/sec) sdc2: real 0m24.953s user 0m0.010s sys 0m6.320s (5.12 MB/sec) sdd2: real 0m31.088s user 0m0.000s sys 0m6.640s (4.11 MB/sec) md0: real 0m35.522s user 0m0.010s sys 0m6.820s (3.60 MB/sec) These values are much lower than previous kernel versions. I don't have the numbers, but it's really true. The RAID0 configuration is set up on two identical QUANTUM drives mentioned above. I don't want to discuss RAID performance, but the slower performace of all my drives. If anyone could comment, if he/she is seeing a similar performance decrease I would be pleased. BTW, the machine has 64MB RAM and the timings do not differ that much from test to test, so I just posted one result for each drive. I know that dd is not a good benchmark and that I could play with the RAID parameters, but it's the same setup I used for month and I just wanted to point out the overall performance decrease, not only the RAID performance. Thanks for your comments, Patrick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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