Date: Fri, 18 Jun 1999 18:20:06 +0930 From: Greg Lehey <grog@lemis.com> To: Darryl Okahata <darrylo@sr.hp.com> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: vinum performance Message-ID: <19990618182006.C2863@freebie.lemis.com> In-Reply-To: <199906180814.BAA29087@mina.sr.hp.com>; from Darryl Okahata on Fri, Jun 18, 1999 at 01:14:20AM -0700 References: <199906180814.BAA29087@mina.sr.hp.com>
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[Format recovered--see http://www.lemis.com/email/email-format.html] On Friday, 18 June 1999 at 1:14:20 -0700, Darryl Okahata wrote: > Greg Lehey <grog@lemis.com> wrote: > >> On Thursday, 17 June 1999 at 3:43:10 -0400, David E. Cross wrote: >>> I have a drive that is rated at ~16 Meg/second, and indeed it >>> delivers on the order of 15+ Meg/second. If I use Vinum to create >>> a concatinated device of 2 such units performance drops to 2.5 >>> Meg/sec. This seems like a drastic drop in performance. >> >> Indeed, if you're comparing apples with apples. > > Possible marginally-related data point: with the 3.1-RELEASE vinum, > and with striped drives (yes, I know the original user is using > concatenated devices), I saw pretty bad write performance with the > default filesystem frag size. Increasing the frag size (via newfs), > increased performance substantially. That shouldn't have anything to do with it. If you see anything unusual in Vinum performance, please tell me. It's easy to come to incorrect conclusions about the cause of performance problems, and disseminating them doesn't help. Follow the links at http://www.lemis.com/vinum.html for a discussion of Vinum performance. The biggest factor influencing Vinum performance on striped plexes is the stripe size, which should be at least 256 kB. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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