From owner-freebsd-hackers Tue Mar 27 16:36:36 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from Awfulhak.org (awfulhak.demon.co.uk [194.222.196.252]) by hub.freebsd.org (Postfix) with ESMTP id 8A8CB37B71A; Tue, 27 Mar 2001 16:36:29 -0800 (PST) (envelope-from brian@Awfulhak.org) Received: from hak.lan.Awfulhak.org (root@hak.lan.Awfulhak.org [172.16.0.12]) by Awfulhak.org (8.11.3/8.11.3) with ESMTP id f2S0aUT65098; Wed, 28 Mar 2001 01:36:30 +0100 (BST) (envelope-from brian@lan.Awfulhak.org) Received: from hak.lan.Awfulhak.org (brian@localhost [127.0.0.1]) by hak.lan.Awfulhak.org (8.11.3/8.11.3) with ESMTP id f2S0eSc03825; Wed, 28 Mar 2001 01:40:28 +0100 (BST) (envelope-from brian@hak.lan.Awfulhak.org) Message-Id: <200103280040.f2S0eSc03825@hak.lan.Awfulhak.org> X-Mailer: exmh version 2.3.1 01/18/2001 with nmh-1.0.4 To: Greg Lehey Cc: Brian Somers , "Michael C . Wu" , dillon@FreeBSD.ORG, fs@FreeBSD.ORG, hackers@FreeBSD.ORG, brian@Awfulhak.org Subject: Re: Vinum stripe size (was: tuning a VERY heavily (30.0) loaded server) In-Reply-To: Message from Greg Lehey of "Wed, 28 Mar 2001 09:50:34 +0930." <20010328095034.M1161@wantadilla.lemis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 28 Mar 2001 01:40:27 +0100 From: Brian Somers Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > On Tuesday, 27 March 2001 at 9:39:36 +0100, Brian Somers wrote: > >> On Tuesday, 20 March 2001 at 11:11:44 -0600, Michael C . Wu wrote: > >>> [Lengthy email, bear with me please, it is quite interesting. > >>> This box averages 30.0 load with no problems.] > >>> > >>> > >>> > >>> Average file size is about 4K. /home/bbsusers* is on a vinum > >>> stripe'd volume with 3 Ultra160 9G 10000RPM drives on sym0 at stripe > >>> size 256K, Greg: I know this should be a prime number, > >> > >> No, there's no requirement for it to be a prime number. The only > >> problem is that with 32 MB cylinder groups and a power of two stripe > >> size and subdisk count, you end up with all the superblocks on one > >> subdisk, which is a performance issue. Choose the stripe size so that > >> the superblocks are roughly evenly distributed. > > > > A performance issue ? Surely you've misspelt ``reliability'' ? > > I don't see a reliability issue here. I believe the only issue with having all your superblocks on one disk is a reliability thing - if you lose the disk you lose your superblock(s). Surely the only performance problem would be that of locality - if you use the partition a bit, that ``problem'' should go away though. > Greg > -- > Finger grog@lemis.com for PGP public key > See complete headers for address and phone numbers -- Brian Don't _EVER_ lose your sense of humour ! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message