Date: Thu, 17 Jun 1999 18:32:25 +0930 From: Greg Lehey <grog@lemis.com> To: Ville-Pertti Keinonen <will@iki.fi> Cc: "David E. Cross" <crossd@cs.rpi.edu>, hackers@FreeBSD.ORG Subject: Re: vinum performance Message-ID: <19990617183225.Q9893@freebie.lemis.com> In-Reply-To: <86so7rqkdg.fsf@not.demophon.com>; from Ville-Pertti Keinonen on Thu, Jun 17, 1999 at 11:52:43AM %2B0300 References: <199906170743.DAA16929@cs.rpi.edu> <86so7rqkdg.fsf@not.demophon.com>
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On Thursday, 17 June 1999 at 11:52:43 +0300, Ville-Pertti Keinonen wrote: > > crossd@cs.rpi.edu (David E. Cross) writes: > >> 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. Any ideas what I am doin incorrectly? > > You've accidentally striped subdisks on the same drive? ;--) > > Like Greg Lehey said, you haven't really provided enough details. He did provide one detail, though; this is a concatenated plex, not a striped one. > The minimum info required would be: > > - Is this read or write performance? That wouldn't be enough. > Many disks are shipped with write caching disabled, and write > performance can be significantly worse than read performance. Not if it works without Vinum. > - Are you testing through the filesystem? (How are you testing?) That's the real qustion. > Maybe you're doing a dd test and accessing /dev/vinum/vol/* rather > than /dev/vinum/rvol/*... That would, in fact, be faster. But we need to know what he's doing, and I suspect you're on the right track. 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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