From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philip Molter Subject: Re: Force parity resync on raid5? Date: Tue, 10 Aug 2004 07:03:52 -0500 Sender: linux-raid-owner@vger.kernel.org Message-ID: <4118B9A8.2040102@corp.texas.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Gordon Henderson wrote: > On Mon, 9 Aug 2004, Philip Molter wrote: > > >>How do I force a parity resync on a raid5 array? Under 2.4, I would do >>this by hard cycling the box and when it came back up, it would >>automatically resync the array. Under 2.6, this appears to have gone away. > > > I don't know about 2.6, (still living with 2.4) but can't you simply do: > > raidhotremove /dev/mdX /dev/hdYZ > > followed by > > raidhotadd /dev/mdX /dev/hdYZ > > or /dev/sdYZ if SCSI disks... > > However, picking the right disk to remove might be tricky... And if you > were at all unsure about data on the disks, maybe rebooting and doing a > hard fsck of the partition(s) in maintenance mode might be a good thing > too... Nope, I want something that will specifically resync the parity from the known good data on the disks. Thanks to the raid5 resync bug from earlier 2.6 kernels, I have hundreds of systems with terabytes of data that have perfectly good data sitting on raid5 arrays with corrupt parity. If I remove a drive to force a resync, the data is immediately corrupted. Linux RAID *has* to have sort of way to force a parity resync. If it doesn't have one, it needs one. That's a glaring omission to make. Philip