From owner-freebsd-performance@FreeBSD.ORG Mon Oct 30 07:08:12 2006 Return-Path: X-Original-To: performance@freebsd.org Delivered-To: freebsd-performance@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8D90E16A40F for ; Mon, 30 Oct 2006 07:08:12 +0000 (UTC) (envelope-from grog@lemis.com) Received: from ext-gw.lemis.com (ext-gw.lemis.com [150.101.14.10]) by mx1.FreeBSD.org (Postfix) with ESMTP id A8F2943D6D for ; Mon, 30 Oct 2006 07:08:11 +0000 (GMT) (envelope-from grog@lemis.com) Received: from wantadilla.lemis.com (wantadilla.lemis.com [192.109.197.135]) by ext-gw.lemis.com (Postfix) with ESMTP id 72F94133129; Mon, 30 Oct 2006 17:38:09 +1030 (CST) Received: by wantadilla.lemis.com (Postfix, from userid 1004) id 5ECD49BF13; Mon, 30 Oct 2006 17:38:09 +1030 (CST) Date: Mon, 30 Oct 2006 17:38:09 +1030 From: Greg 'groggy' Lehey To: "R. B. Riddick" Message-ID: <20061030070809.GJ1052@wantadilla.lemis.com> References: <20061030051913.GG1052@wantadilla.lemis.com> <20061030070532.5495.qmail@web30309.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="4vpci17Ql0Nrbul2" Content-Disposition: inline In-Reply-To: <20061030070532.5495.qmail@web30309.mail.mud.yahoo.com> User-Agent: Mutt/1.4.2.1i Organization: The FreeBSD Project Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-418-838-708 VoIP: sip:0871270137@sip.internode.on.net WWW-Home-Page: http://www.FreeBSD.org/ X-PGP-Fingerprint: 9A1B 8202 BCCE B846 F92F 09AC 22E6 F290 507A 4223 Cc: performance@freebsd.org Subject: Re: gvinum raid5 performance seems slow X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 30 Oct 2006 07:08:12 -0000 --4vpci17Ql0Nrbul2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sunday, 29 October 2006 at 23:05:32 -0800, R. B. Riddick wrote: > --- Greg 'groggy' Lehey wrote: >> "Sufficiently large data blocks" equates to several megabytes. >> Currently MAXPHYS, the largest transfer request that would get to the >> bio layer, is 131072 bytes. This would imply a stripe size of not >> more than 32 kB for a five disk array, which is unrealistically small. >> >> I did consider this optimization, but it would only work if Vinum were >> first to buffer multiple requests, and there are all sorts of >> reliability issues there. For example, you'd have to lie about the >> first few requests that were only buffered and not actually sent out >> to disk. Possibly it should be done anyway. >> > I did it that way in my graid5 class: > http://home.tiscali.de/cmdr_faako/geom_raid5.tbz I would have taken a look at it if the sources had been directly web viewable. > The source might look somehow incomprehensible, Heh. I know the feeling :-) > but it seems to be quite stable (on amd64 and i386)... > > > I tried to benchmark with a 3 disk array: > Single disk: 30MB/sec write speed > graid5 device: 20MB/sec write speed Can you give more details? Stripe size, request size, number of concurrent accessors, etc.? > I would be interested in other benchmarks about it. Try rawio. Greg -- See complete headers for address and phone numbers. --4vpci17Ql0Nrbul2 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (FreeBSD) iD8DBQFFRaTZIubykFB6QiMRArD6AJ4ygV+/v2wMI9+pOnBAWDYE9yecPACfTA18 0K8V4QRRIS1wG+qq14zlb4k= =R5eA -----END PGP SIGNATURE----- --4vpci17Ql0Nrbul2--