From mboxrd@z Thu Jan 1 00:00:00 1970 From: Helge Hafting Subject: Re: Sharing disks amoung multiple software RAIDs Date: Fri, 02 May 2008 15:43:25 +0200 Message-ID: <481B1A7D.2020000@aitel.hist.no> References: <1209692359.16523.2.camel@localhost> <73000.21239.qm@web50212.mail.re2.yahoo.com> <1209696179.16523.13.camel@localhost> <72dbd3150805020006p7f976a04o487389840f03b4a2@mail.gmail.com> <1209715763.7827.2.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1209715763.7827.2.camel@localhost> Sender: linux-raid-owner@vger.kernel.org To: Kasper Sandberg Cc: David Rees , David Lethe , alex14641@yahoo.com, Justin Piszcz , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-raid.ids Kasper Sandberg wrote: > On Fri, 2008-05-02 at 00:06 -0700, David Rees wrote: > >> On Thu, May 1, 2008 at 7:42 PM, Kasper Sandberg wrote: >> >>> in other words, would i be >>> safer to run rsync every day to my other disk, and run in non-raid >>> mode?! >>> >> What would be safer is to run rsync every day from one redundant array >> to another array - preferably on another machine that is located as >> far away as possible from the one that you are backing up. >> >> RAID is not the same as a backup, though unfortunately, too many >> people treat it as such. >> > Im not treating it as a backup, what i want, is to make sure that if 1 > disk dies, the data is still intact and ill hopefully be able to run > with 1 disk till the newly ordered one arrives - and while i naturally > will keep offsite backups of most important data, it is certainly far > easier to simply rip out a faulty disk, and put in another, instead of > restoring from backup from scratch.. > > So my question remains.. Is md raid1 not suited for this need? would it > be safer to run in non-raid1 mode and daily(maybe hourly) rsync > everything over to the second disk? > Raid protects against disk failure. So your use is fine. Backup also protects against user error and virus/worm/cracker damage. If you accidentally overwrite a file, or a virus/worm/cracker messes up the filesystem, then RAID loose because the overwiting/messing happens on both disks. In that case you'll still be able to get stuff from a backup. Helge Hafting