From owner-freebsd-stable Wed Sep 6 17:57:53 2000 Delivered-To: freebsd-stable@freebsd.org Received: from wantadilla.lemis.com (wantadilla.lemis.com [192.109.197.80]) by hub.freebsd.org (Postfix) with ESMTP id EC92437B423; Wed, 6 Sep 2000 17:57:48 -0700 (PDT) Received: (from grog@localhost) by wantadilla.lemis.com (8.11.0/8.9.3) id e870vet14679; Thu, 7 Sep 2000 10:27:40 +0930 (CST) (envelope-from grog) Date: Thu, 7 Sep 2000 10:27:40 +0930 From: Greg Lehey To: Mike Smith Cc: Mike Tancsa , Tim Tsai , stable@FreeBSD.ORG Subject: Re: Vinum (was: RAID) Message-ID: <20000907102740.B7718@wantadilla.lemis.com> References: <20000906084835.B21113@wantadilla.lemis.com> <200009052339.QAA03602@mass.osd.bsdi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <200009052339.QAA03602@mass.osd.bsdi.com>; from msmith@FreeBSD.ORG on Tue, Sep 05, 2000 at 04:39:48PM -0700 Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-418-838-708 WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tuesday, 5 September 2000 at 16:39:48 -0700, Mike Smith wrote: >>> Just about to test and compare the same Atlas IV drives (QUANTUM ATLAS IV 9 >>> WLS 0B0B) usings a 2940U2 (aic7890/91) with vinum. I will post the results >>> with the same three SCSI drives in the various adaptors in RAID5 (3 drive >>> config) when done. >> >> Please make sure to use rawio in the tests. Other things, such as >> bonnie and dd, give better looking results, but they're not very >> related to what happens in practice. > > Rawio is largely a seek-time tester, Correct. That's the biggest issue in disk I/O. > and not particularly representative of real-world I/O loads either. It's reasonably close. It could always be better, of course, and as discussed I'm planning to write code to snapshot real-life disk activity. In the meantime, I think the current version is relatively accurate. What specific problems do you see? > To get a feel for how a controller interacts with the buffer cache, > you need to present the load via the filesystem. No, you just need to present the same kind of load. > I typically use a large number of bonnie processes (20 or so) > working with large datasets (1-10GB) and then ignore their output > and instead monitor the controller's throughput using devstat. > Other filesystem load generators are probably worth considering as > well, since bonnie's I/O patterns are not very imaginiative. Nor are they particularly representative of real-world I/O loads :-) In addition, monitoring devstat output requires a lot of interpretation. 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-stable" in the body of the message