From owner-freebsd-hackers Thu Jun 17 1:17:59 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (Postfix) with ESMTP id D791C15724 for ; Thu, 17 Jun 1999 01:17:40 -0700 (PDT) (envelope-from grog@freebie.lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.9.1/8.9.0) with ESMTP id RAA03685; Thu, 17 Jun 1999 17:47:41 +0930 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id RAA52025; Thu, 17 Jun 1999 17:47:47 +0930 (CST) Date: Thu, 17 Jun 1999 17:47:47 +0930 From: Greg Lehey To: "David E. Cross" Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: vinum performance Message-ID: <19990617174746.N9893@freebie.lemis.com> References: <199906170743.DAA16929@cs.rpi.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.4i In-Reply-To: <199906170743.DAA16929@cs.rpi.edu>; from David E. Cross on Thu, Jun 17, 1999 at 03:43:10AM -0400 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 Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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. > Any ideas what I am doin incorrectly? No. You haven't really given any details. Most of the performance testing I have done has been with striped plexes (which offer the potential for better performance), and I've found that in massively concurrent situations the performance is roughly what you would expect (almost n * normal disk performance, where n is the number of disks in the stripe set. I'd expect performance of a concatenated plex to be pretty close to that of the raw disk. How are you measuring performance? I'd recommend rawio (ftp://ftp.lemis.com/pub/rawio.tar.gz). 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