From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Scobie Subject: Re: Linux Software RAID a bit of a weakness? Date: Sat, 24 Feb 2007 17:14:53 +1300 Message-ID: <45DFBBBD.7020808@sauce.co.nz> References: <1172258378.21648.51.camel@cowie> <17887.19894.548422.683023@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17887.19894.548422.683023@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Neil Brown wrote: > The 'check' process reads all copies and compares them with one > another, If there is a difference it is reported. If you use > 'repair' instead of 'check', the difference is arbitrarily corrected. > If a read error is detected during the 'check', md/raid1 will attempt > to write the data from the good drive to the bad drive, then read it > back. If this works, the drive is assumed to be fixed. If not, the > bad drive is failed out of the array. > One thing to note here is that 'repair' was broken for RAID1 until recently - see http://marc.theaimsgroup.com/?l=linux-raid&m=116951242005315&w=2 As this patch was submitted just prior to the release of 2.6.20, this may be the first "fixed" kernel, but I have not checked. Regards, Richard