Date: Thu, 10 May 2001 13:34:25 +0930 From: Greg Lehey <grog@lemis.com> To: Scott Mace <smace@intt.org> Cc: Dan Phoenix <dphoenix@bravenet.com>, FreeBSD Questions <questions@FreeBSD.ORG> Subject: Re: vinum on 2 ide drives? Message-ID: <20010510133425.K56501@wantadilla.lemis.com> In-Reply-To: <BFENLHFJOCHGGGAHGHOPKEADCCAA.smace@intt.org>; from smace@intt.org on Wed, May 09, 2001 at 10:46:43PM -0500 References: <20010510125406.I56501@wantadilla.lemis.com> <BFENLHFJOCHGGGAHGHOPKEADCCAA.smace@intt.org>
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On Wednesday, 9 May 2001 at 22:46:43 -0500, Scott Mace wrote: > I'm seeing the same behaviour with a pair of IBM drives. I even made sure > that > write cache was enabled... I'm using 307030's > > This is on a regular non-vinum partition > > onix2# iozone 128 8192 > > IOZONE: Performance Test of Sequential File I/O -- V2.01 (10/21/94) > > IOZONE writes a 128 Megabyte sequential file consisting of > 16384 records which are each 8192 bytes in length. > It then reads the file. It prints the bytes-per-second > rate at which the computer can read and write files. This is not really relevant to real-life access. But it might explain Dan's issues: sequential access to a stripe will be slower than to a concat plex such as you're using. > IOZONE performance measurements: > 21746669 bytes/second for writing the file > 29671622 bytes/second for reading the file > > This is on a vinum mirror. > > IOZONE performance measurements: > 10784600 bytes/second for writing the file > 24437936 bytes/second for reading the file It's difficult to guess what's going on here. Looking at your configuration below, I'd guess that you're not comparing things directly. > drive vinumdrive0 device /dev/ad0s1e > drive vinumdrive2 device /dev/ad0s1f > drive vinumdrive4 device /dev/ad0s1g > drive vinumdrive1 device /dev/ad1s1e > drive vinumdrive3 device /dev/ad1s1f > drive vinumdrive5 device /dev/ad1s1g These are four drives too many. You don't want more than one drive per spindle. Greg -- Finger grog@lemis.com for PGP public key See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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