From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?U2VyZ2l1c3ogQnJ6ZXppxYRza2k=?= Subject: Re: mdadm --monitor: need extra feature? Date: Tue, 21 Aug 2012 13:51:48 +0200 Message-ID: <50337654.9000905@supersystem.pl> References: <503365EB.6000006@supersystem.pl> <503366A1.9030307@hesbynett.no> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <503366A1.9030307@hesbynett.no> Sender: linux-raid-owner@vger.kernel.org To: David Brown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids W dniu 21.08.2012 12:44, David Brown pisze: > On 21/08/2012 12:41, Sergiusz Brzezi=C5=84ski wrote: >> Hi, >> >> I use Raid1 to make backup of the whole system. > > Raid is not a backup system. It is to improve uptimes, minimise downt= imes due to > disk failures, and possibly to improve disk speed and/or capacity. > > I would recommend you first think about what you are trying to achiev= e here - > what are you trying to back up, how do you see restores being used, h= ow > efficiently are you using your hardware, your bandwidth, your time an= d effort? > > You would probably be better off with a normal fixed 2-disk raid1 to = minimise > the problems caused by a single disk failure, combined with an rsync = snapshot > style backup that can be fully automated and give quick and easy reco= very of > multiple old versions of files in the face of the most common cause o= f data loss > - human error. [...] I know, I know. Raid is not a backup system :) Or better: it is not intended to be a backup system. But I do use Raid1 as backup solution because I don't know another back= up=20 solution giving me together: - so simple configuration (there is no configuration!) - so low cost (no software cost, only hdd cost) - complete copy of the whole system (not only data but also configurati= on) - so quick start in case of hardware failure - so fast backup process without excessive system load - so simple handling (just remove and insert hdd with hot-swap bay) With some more rotating disks it can simulate very good backup solution= s and I=20 still can make backups of critical data (dumping databases, copying fil= es)=20 independently of Raid (and I do it). And even I You don't want using it as a regular backup it is alwas wort= h to do a=20 bootable disk with mirrored system partition and keep it somewhere out = of the=20 box for the bad times - just a small system backup for quick start in c= ase of=20 hardware failure. So, maybye Raid 1 is not a backup system but for some cases this is the= best=20 backup solution it can be! And I am an opportunist :) Sergiusz -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html