Date: Tue, 25 Feb 2003 10:00:55 +0100 From: =?iso-8859-1?Q?=C5ge_R=F8bekk?= <aagero@eunetnorge.no> To: freebsd-scsi@freebsd.org Subject: performance issues with amr driver, dell PERC 3/DC Message-ID: <20030225090055.GI76052@eunetnorge.no>
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I have a Dell Poweredge 2650 with a Dell PERC 3/DC RAID card. Both channels on the controller are connected to a PowerVault 220S enclosure. The PV220S has 8 disks, 4 on each channel (split backplane). For some reason, I cannot get speeds higher than ~14MB/s, even with a RAID-0 stripe on all disks. In another setup, with a RAID-5 set on one channel (4 disks) and a RAID-0 set on the other channel, there is no difference in write performance, not what one should expect. If I run 2 dd's, one on each of the RAID5/RAID0 sets, the throughput is divided in half, ~7MB/s, for each channel. Which suggests the problem more likely located in the driver rather than the scsi bus speeds, etc. Another strange thing is that transfers per second (tps in iostat) is always very close to 150 tps, and with a max iosize of 96k, the througput is as expected, 150 * 96k ~= 14MB/s. This system is running the latest RELENG_4 sources as of Feb 24. -- Åge Røbekk, EUnet Norge AS To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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