From owner-freebsd-questions@FreeBSD.ORG Tue Jan 29 14:57:32 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 61D13517 for ; Tue, 29 Jan 2013 14:57:32 +0000 (UTC) (envelope-from wblock@wonkity.com) Received: from wonkity.com (wonkity.com [67.158.26.137]) by mx1.freebsd.org (Postfix) with ESMTP id 091C2FFE for ; Tue, 29 Jan 2013 14:57:31 +0000 (UTC) Received: from wonkity.com (localhost [127.0.0.1]) by wonkity.com (8.14.6/8.14.6) with ESMTP id r0TEvVTr027782; Tue, 29 Jan 2013 07:57:31 -0700 (MST) (envelope-from wblock@wonkity.com) Received: from localhost (wblock@localhost) by wonkity.com (8.14.6/8.14.6/Submit) with ESMTP id r0TEvVRn027779; Tue, 29 Jan 2013 07:57:31 -0700 (MST) (envelope-from wblock@wonkity.com) Date: Tue, 29 Jan 2013 07:57:31 -0700 (MST) From: Warren Block To: Artem Kuchin Subject: Re: Software raid VS hardware raid In-Reply-To: <5107A500.4030902@itlegion.ru> Message-ID: References: <5106E301.4070707@itlegion.ru> <5107A500.4030902@itlegion.ru> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (wonkity.com [127.0.0.1]); Tue, 29 Jan 2013 07:57:31 -0700 (MST) Cc: freebsd-questions@freebsd.org X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 29 Jan 2013 14:57:32 -0000 On Tue, 29 Jan 2013, Artem Kuchin wrote: > My other concern is what happens when one drive goes down if we use gmirror? > Is it completelly transparent > and bad drive can be hot swapped while server is running and rebuild started? > I am thinking now about gpt+gmirror (including boot and swap) As far a gmirror is concerned, yes, drives can be removed and new drives inserted while the mirror is running. Hot swap is more of an issue with the hardware. I have not tried it with SATA drives, although I think it should work. The Handbook chapter on gmirror talks about the problems with GPT and GEOM metadata. In short: right now, they conflict. It's possible to mirror GPT partitions, but be aware that if you mirror more than one partition on a drive, a rebuild after replacing a drive could thrash the heads as mirrors are rebuilt simultaneously. http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/geom-mirror.html