From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: After partition resize, RAID5 array does not assemble on boot Date: Fri, 06 Jun 2008 09:52:45 -0400 Message-ID: <4849412D.9030607@tmr.com> References: <4844E994.8020808@jellybean.co.uk> <4845B573.7090801@jellybean.co.uk> <48675.192.168.1.70.1212528422.squirrel@neil.brown.name> <484636B9.20700@jellybean.co.uk> <48464B3A.7070206@dgreaves.com> <4846529B.1000809@jellybean.co.uk> <484681AF.8030004@dgreaves.com> <48469523.4050601@jellybean.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <48469523.4050601@jellybean.co.uk> Sender: linux-raid-owner@vger.kernel.org To: Jules Bean Cc: David Greaves , NeilBrown , linux-raid@vger.kernel.org List-Id: linux-raid.ids Jules Bean wrote: > David Greaves wrote: >>> I don't really see that it's "safer" though. I would have thought it >>> was >>> quicker but potentially less safe. >> >> Avoiding a lot of time stress testing the disks in degraded mode >> isn't 'safer'? > > Stress testing the disks by an md rebuild is a feature! It increases > confidence that they work. > > ;) > > Seriously, I understand your point now. Yes, a rebuild-free partition > resize would be a nice feature. So would a "help, please find my > superblock by exhaustive scanning" utility ;) Since this code must work when a partition is added on a totally new drive, and when the partition is grown DOWN from the low end, clearly the default must be a rebuild. And running "repair" before doing this stuff is a really good idea! What is needed is to do something like assume-clean on the old data and a sync on the new chunks. I don't see that there is a remotely safe way to do that, currently, although if you were willing to be unsafe you could remove a partition, grow it at the "top" end, and reassemble with --assume-clean. Sprinkling with holy water first might be a good thing. I'm just thinking out loud here, there are probably good reasons why this wouldn't work. -- Bill Davidsen "Woe unto the statesman who makes war without a reason that will still be valid when the war is over..." Otto von Bismark