From owner-freebsd-questions Thu Apr 26 16:13:35 2001 Delivered-To: freebsd-questions@freebsd.org Received: from wantadilla.lemis.com (wantadilla.lemis.com [192.109.197.80]) by hub.freebsd.org (Postfix) with ESMTP id 06ED037B423 for ; Thu, 26 Apr 2001 16:13:30 -0700 (PDT) (envelope-from grog@lemis.com) Received: by wantadilla.lemis.com (Postfix, from userid 1004) id 3B1C06ACB8; Fri, 27 Apr 2001 08:43:28 +0930 (CST) Date: Fri, 27 Apr 2001 08:43:28 +0930 From: Greg Lehey To: Scott Culverhouse Cc: questions@FreeBSD.ORG Subject: Re: vinum - mirroring! Message-ID: <20010427084328.C70059@wantadilla.lemis.com> References: <20010426111634.C3FC.SCOTT.CULVERHOUSE@opencube.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20010426111634.C3FC.SCOTT.CULVERHOUSE@opencube.co.uk>; from scott.culverhouse@opencube.co.uk on Thu, Apr 26, 2001 at 11:19:27AM +0100 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-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Thursday, 26 April 2001 at 11:19:27 +0100, Scott Culverhouse wrote: > Hi we have a machine with 2 x 36Gb SCSI drives and we want to put var > and usr on to 2 vinum volumes. But we want both performance and > resilience can they be done with two drives only? > > Here is a config I propose but not sure whether it will work too well or > not:- Is it ok? > > drive sd0 device /dev/da0e > drive sd1 device /dev/da0f You shouldn't put more than one drive on a spindle. > drive sd2 device /dev/da1e > drive sd3 device /dev/da1h > > volume var > plex org striped 256k You don't want a stripe size which is a power of 2. > sd length 5g drive sd0 > sd length 5g drive sd1 > plex org striped 256k > sd length 5g drive sd2 > sd length 5g drive sd3 > > volume usr > plex org striped 256k > sd length 10g drive sd0 > sd length 10g drive sd1 This would give you terrible performance like this. You'd be adding gratuitous seeks. The two subdisks should be on different spindles. > plex org striped 256k > sd length 10g drive sd2 > sd length 10g drive sd3 > > The reason I created 4 drives (2 slices on each drive) is so I could > have 2 drives per plex is the a good or bad idea! It's a bad idea. That's what we have subdisks. Try this: drive a device /dev/da0e drive b device /dev/da1e volume var plex org striped 273k sd length 5g drive a sd length 5g drive b plex org striped 273k sd length 5g drive b sd length 5g drive a volume usr plex org striped 273k sd length 10g drive a sd length 10g drive b plex org striped 273k sd length 10g drive b sd length 10g drive a Note that the subdisks on the second plex are the other way round; otherwise the failure of a drive would cause you to lose half the volume, which is obviously not what you want. > What size var and usr will this give me 5g and 10g respectively! This will give you 10g and 20g respectively. Greg -- When replying to this message, please copy the original recipients. If you don't, I may ignore the reply. For more information, see http://www.lemis.com/questions.html 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-questions" in the body of the message