From owner-freebsd-questions Sun Dec 8 15:46: 0 2002 Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A340837B401 for ; Sun, 8 Dec 2002 15:45:58 -0800 (PST) Received: from wantadilla.lemis.com (wantadilla.lemis.com [192.109.197.80]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3677343EA9 for ; Sun, 8 Dec 2002 15:45:57 -0800 (PST) (envelope-from grog@lemis.com) Received: by wantadilla.lemis.com (Postfix, from userid 1004) id 4D3FA5190A; Mon, 9 Dec 2002 10:15:55 +1030 (CST) Date: Mon, 9 Dec 2002 10:15:55 +1030 From: Greg 'groggy' Lehey To: Mark Rowlands Cc: questions@freebsd.org Subject: Re: couple of vinum questions from a vinum newbie. Message-ID: <20021208234555.GO96646@wantadilla.lemis.com> References: <200212081704.28492.fuc952d@tninet.se> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200212081704.28492.fuc952d@tninet.se> User-Agent: Mutt/1.4i Organization: The FreeBSD Project Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-418-838-708 WWW-Home-Page: http://www.FreeBSD.org/ X-PGP-Fingerprint: 9A1B 8202 BCCE B846 F92F 09AC 22E6 F290 507A 4223 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sunday, 8 December 2002 at 17:04:28 +0100, Mark Rowlands wrote: > I have decided to dip my toe into the vinum waters primarily for improved read > performance, not redundancy or reliability. I have backups for that ;-). > > I have two questions, one related to optimal stripe size and one to gathering > statistics. > > I have a freshly cvsupped 4.7 stable currently installed on a 30g single disk > I propose to add a second 30gb disk as a mirror of this. and to add two new > identical disks (maxtor fdb-9 120gb) and create a striped volume for data on > those. > > I propose (maybe) to create a single striped volume but...... what stripe > size? Reading the various vinum docs and looking at some of the samples > I found lying around the web left me a touch confused. > > There are two categories of files on the data disk, largeish ( 4-5mb) which > are most frequently accessed but the overwhelming majority of files are much > smaller (<4k) but not accessed so frequently. > > So, is it better to try and optimize for the most frequently accessed, or the > filesize that comprises the bulk of file accesses? or better to create two > volumes with different stripe sizes. In either case, if anyone has any > concrete recommendations, I would welcome them. > > When the new hardware arrives, (about a week), I will probably run some tests > with varying stripe-sizes and see what happens but any pointers towards > likely good starting points...... There's a fair discussion of stripe sizes in vinum(4), about 200 lines long, under the heading "Performance considerations". I can't do better than that in less space. What part of that don't you understand? Greg -- When replying to this message, please copy the original recipients. If you don't, I may ignore the reply or reply to the original recipients. For more information, see http://www.lemis.com/questions.html 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