From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Coffman Subject: Device naming and raid1 Date: Tue, 26 Aug 2008 11:32:54 -0400 Message-ID: <48B42226.3020702@emitony.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids I've have a Centos5 box running a software raid-1 set on a pair of SATA drives. The SATA controller or driver has a flaw. Every 150 days or so, one of the two drives will experience errors and fail. Subsequent tests always show the drive and cable to be ok. We bought a couple of replacement drives before we figured that out :-( On the last event this weekend, I went searching for a way to get the raid back online with no host downtime. I found the technique that deletes the drive and then brings it back online with a bus scan using the /sys filesystem delete and rescan entities. I didn't realize that you could also perform a rescan on a single LUN. I'll have to use that next time. My question - since I've done a delete/rescan bus operation, my device name and major,minor numbers have changed. Original [0:0:0:0] disk ATA ST3250410AS 3.AA /dev/sdc Current [0:0:0:0] disk ATA ST3250410AS 3.AA /dev/sdc If I re-add the device to the raid set using the new device name, will it cause any problems on the next boot? The drive appears to be fine. I can read all blocks with no errors. Partition table looks ok, etc.. In the future if I rescan just the single LUN, I'm pretty sure I won't run into again this but I'd like to avoid an outage on this event if possible. Thanks and regards, --Tony