From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: Re: Expanding RAID array? Date: Tue, 17 Jan 2006 10:43:44 +0400 Message-ID: <43CC9220.8000800@wasp.net.au> References: <1137424449.3953.38.camel@kenny> <17356.8228.325002.652805@cse.unsw.edu.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17356.8228.325002.652805@cse.unsw.edu.au> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: John Rowe , linux-raid@vger.kernel.org List-Id: linux-raid.ids Neil Brown wrote: > - add disks to convert to raid6. > I don't think this is possible, but you should check the latest > raid reconfig. It's not. I started work on it Feb last year but then real life got in the way again. In the longer term, I think raidreconf as it stands is going to die (mainly because it's infrastructure relies on the old raidtab architecture). I thought about perhaps porting it as an addon to mdadm, but then I ran out of drives/machines/time to test it on. > Might be supported online with a limited raid6 in which the Q > syndrome (second 'parity' block) isn't rotated among disks. In theory I would have thought it not that much different than a raid-5 expand, just inserting an extra block for the Q syndrome. > - status of RAID6 > I believe it is as stable/reliable as raid5. Mine has been running since Feb last year with fairly moderate use and no hiccups. I have just upgraded to the latest 2.6.15-git on that machine to give some of the newer raid patches (like check & repair) a whirl. Seems fairly solid. Let's say I've never had any raid-6 related data loss, or even near misses, but it has saved my bacon in 2 dual drive failures in the last year. Oh, and the new read and check code (rather than just rebuild the parity blocks) shaves about 1 hour of what was an 11 hour rebuild time on this particular raid-6. Thanks Neil! Regards, Brad -- "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." -- Douglas Adams