[CentOS] GFS/LVM/RAID1 recovery question

Mon Jul 23 16:33:57 UTC 2007
James Fidell <james at cloud9.co.uk>

Tru Huynh wrote:
> On Mon, Jul 23, 2007 at 04:07:57PM +0100, James Fidell wrote:
> ...
>>   lvcreate -m 1 ... /dev/sdb /dev/sdc /dev/sdd
> 
> or use pvreate /dev/md0 (md raid1 mirror of sda/sdb/sdc)?

AIUI, MD isn't cluster-{aware,safe} though, so I could end up with all
the servers that can see the physical disks trying to do stuff with the
mirrors individually, making a horrible mess?

(In my configuration, all servers mount the iSCSI devices and I'm using
LVM/clvmd to allow them to keep everything sane and remove any single
point of failure.)

>> where sd[bc] are the mirrored (iSCSI) PVs in the VG and sdd is the log.
>> I have this working and can write data to the filesystem on one machine
>> in the cluster and see it appear elsewhere etc.
>>
>> What I now want to do is to test what happens when I disable one
>> of the mirrors and then restore it with clean disks.
> http://mirror.centos.org/centos/4/docs/4.5/SAC_Cluster_Logical_Volume_Manager/mirrorrecover.html

Perfect.  That's exactly what I was after.  Thank you.

James