From owner-freebsd-questions@FreeBSD.ORG Tue Jul 10 10:26:08 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 1B652106566B for ; Tue, 10 Jul 2012 10:26:08 +0000 (UTC) (envelope-from wojtek@wojtek.tensor.gdynia.pl) Received: from wojtek.tensor.gdynia.pl (wojtek.tensor.gdynia.pl [89.206.35.99]) by mx1.freebsd.org (Postfix) with ESMTP id 759448FC1D for ; Tue, 10 Jul 2012 10:26:07 +0000 (UTC) Received: from wojtek.tensor.gdynia.pl (localhost [127.0.0.1]) by wojtek.tensor.gdynia.pl (8.14.5/8.14.5) with ESMTP id q6AAQ7Lo047129; Tue, 10 Jul 2012 12:26:07 +0200 (CEST) (envelope-from wojtek@wojtek.tensor.gdynia.pl) Received: from localhost (wojtek@localhost) by wojtek.tensor.gdynia.pl (8.14.5/8.14.5/Submit) with ESMTP id q6AAQ64c047126; Tue, 10 Jul 2012 12:26:07 +0200 (CEST) (envelope-from wojtek@wojtek.tensor.gdynia.pl) Date: Tue, 10 Jul 2012 12:26:06 +0200 (CEST) From: Wojciech Puchar To: Bas Smeelen In-Reply-To: <4FFC013A.3040903@ose.nl> Message-ID: References: <4FFBEE6E.6000906@ulb.ac.be> <4FFC013A.3040903@ose.nl> 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 passed SPF test, not delayed by milter-greylist-4.2.7 (wojtek.tensor.gdynia.pl [127.0.0.1]); Tue, 10 Jul 2012 12:26:07 +0200 (CEST) Cc: freebsd-questions@freebsd.org Subject: Re: FreeBSD 9.0 & LSI MegaRAID SATA problem X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Jul 2012 10:26:08 -0000 > > That's clear to me. > These "hardware" raid controllers are not very reliable because they are > indeed not real hardware raid controllers, but software based. > Maybe for desktop usage it's ok/ good enough? precise what is "desktop" usage is. i don't see a reason for doing mirroring for home use. > It is better to use the operating systems raid capability linke gmirror > instead. > always. > Of course real hardware raid controllers with cache and battery backed are a > different thing and very reliable. if you have workload where battery backed cache will actually improve things (heavy fsync usage) then yes. otherwise no. i've seen many of them, older, newer, and with same disks i always got at least same performance with FreeBSD software solution. Not talking about RAID5 of which i am not interested at all - there is no reason trading performance for available space nowadays with 2-3TB disks.