From owner-freebsd-stable@FreeBSD.ORG Wed Jun 17 07:56:41 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 214F9106564A for ; Wed, 17 Jun 2009 07:56:41 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from asmtpout022.mac.com (asmtpout022.mac.com [17.148.16.97]) by mx1.freebsd.org (Postfix) with ESMTP id 862838FC12 for ; Wed, 17 Jun 2009 07:56:40 +0000 (UTC) (envelope-from cswiger@mac.com) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Received: from [17.151.103.111] by asmtp022.mac.com (Sun Java(tm) System Messaging Server 6.3-8.01 (built Dec 16 2008; 32bit)) with ESMTPSA id <0KLD007L2I2FPO40@asmtp022.mac.com> for freebsd-stable@freebsd.org; Wed, 17 Jun 2009 00:56:40 -0700 (PDT) Message-id: <92485F5A-C600-4514-959A-2562CE416DEB@mac.com> From: Chuck Swiger To: Andrew Reilly In-reply-to: <20090617005335.GA27257@duncan.reilly.home> Date: Wed, 17 Jun 2009 00:56:39 -0700 References: <20090616185312.GJ9529@server.vk2pj.dyndns.org> <20090617005335.GA27257@duncan.reilly.home> X-Mailer: Apple Mail (2.935.3) Cc: freebsd-stable@freebsd.org Subject: Re: Does this disk/filesystem layout look sane to you? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Jun 2009 07:56:41 -0000 Hi-- On Jun 16, 2009, at 5:53 PM, Andrew Reilly wrote: > I bought a pair of identical WD 750G SATA drives the other day > and was surprised to discover that they were different sizes: > > ad4: 715403MB at ata2-master SATA150 > ad6: 715404MB at ata3-master SATA150 > > Luckily for me I built the file systems on ad4, and added ad6 to > the gmirror configuration. I suspect that it would have been > unhappy if I'd done it the other way around. Agreed. However, you might want to look carefully at the first drive via smartctl or even WDC's own utilities. It's not unusual for a drive to have some small area(s) of the disk surface which cannot record data reliably and hence are marked as bad sectors in the initial factory-provided P-LIST, and to keep some reserves as spare sectors for bad sectors which happen during normal operation (the 'grown' list aka G-LIST). If that is the reason (and there could be others-- you might even want to ping WDC's tech support about this), it's surprising that the amount of sectors marked bad is enough to change the reported size in megabytes. You might also want to double-check the actual physical label on the drive and watch out for an "RM" or "remanufactured"/"recertified" indicator. Regards, -- -Chuck