From owner-freebsd-questions Fri Sep 3 17:35:15 1999 Delivered-To: freebsd-questions@freebsd.org Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (Postfix) with ESMTP id 3216814C49 for ; Fri, 3 Sep 1999 17:35:05 -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 JAA25370; Sat, 4 Sep 1999 09:40:20 +0930 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id JAA03901; Sat, 4 Sep 1999 09:40:18 +0930 (CST) Date: Sat, 4 Sep 1999 09:40:18 +0930 From: Greg Lehey To: Gerd Knops Cc: questions@FreeBSD.ORG Subject: Re: Vinum: Best performance from mirror setup with two disks Message-ID: <19990904094018.A95378@freebie.lemis.com> References: <19990903232137.9612.qmail@camelot.bitart.com> <19990904090824.Y95378@freebie.lemis.com> <19990903235501.9687.qmail@camelot.bitart.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.4i In-Reply-To: <19990903235501.9687.qmail@camelot.bitart.com>; from Gerd Knops on Fri, Sep 03, 1999 at 06:55:00PM -0500 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-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Friday, 3 September 1999 at 18:55:00 -0500, Gerd Knops wrote: > Greg Lehey wrote: >> On Friday, 3 September 1999 at 18:21:36 -0500, Gerd Knops wrote: >>> Hi, >>> >>> I have read everything I could find about vinum (man pages, recent >>> questions Mailing list, Vinum intro) but I am still not quite sure: >>> >>> What is the best performing setup to get mirroring with two disks? >>> >>> I understand that I just set up one plex per disk. Write performance goes >>> down due to double writes, read performance goes up since vinum will >>> alternate reads between the plexis. >> >> Correct. >> >>> What I don't quite understand is if striping gives me an added advantage >>> in this scenario. >> >> It depends a lot on your usage. In general, a striped plex will give >> more even access to the two drives, so the performance is likely to be >> better. >> > I still don't get that. In the case of a two disk mirror, how can striping > help performance if reads are already alternated between the two plexes > (which are on different disks)? I didn't say it would help read performance, but it'll help write performance. Don't expect to see a big improvement, though. Greg -- When replying to this message, please copy the original recipients. For more information, see http://www.lemis.com/questions.html 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-questions" in the body of the message