Date: Tue, 25 Feb 2003 10:56:17 -0500 From: "Moore, Eric Dean" <emoore@lsil.com> To: =?iso-8859-1?Q?=C5ge_R=F8bekk?= <aagero@eunetnorge.no>, freebsd-scsi@FreeBSD.ORG Subject: RE: performance issues with amr driver, dell PERC 3/DC Message-ID: <0E3FA95632D6D047BA649F95DAB60E5701DE5DE1@EXA-ATLANTA.se.lsil.com>
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Please send me your dmesg. =20 (1) I need to know what command line options you were using when = running dd; e.g was it reads or writes, and what benchmark tool you used to get 7MB/s. (2) dumbquestion: iostat, how did you set 96k iosize? (3) When was the last good kernel you had with acceptable benchmarks. (4) Also, in control M, when is your read and write cache set to? Eric Moore On Tuesday, February 25, 2003 4:01 AM, =C5ge R=F8bekk=20 >=20 > 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=20 > 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. >=20 > 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. >=20 > 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 ~=3D 14MB/s. >=20 > This system is running the latest RELENG_4 sources as of Feb 24. >=20 > --=20 > =C5ge R=F8bekk, EUnet Norge AS >=20 > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-scsi" in the body of the message >=20 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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