On Mar 21, 2011, at 3:21 PM, Emmanuel Noobadmin <centos.admin at gmail.com> wrote: >> Since your exporting the storage as iSCSI, the host machine will see >> it as a raw disk, irrespective of how it's setup on the exported >> server. So, yes, you can do this. > > Sorry for my ambiguity, I meant that mdadm would be on the host machine. > > e.g. Using just a 2 node, raid 1 situation > Storage 1 > -> Disk exported on 192.168.1.10, 192.168.2.10 > > Storage 2 > -> Disk exported on 192.168.1.20, 192.168.2.20 > > Host > -> mdadm multipath md0 = 192.168.1.10, 192.168.2.10 > -> mdadm multipath md1 = 192.168.1.20, 192.168.2.20 > ---> mdadm raid 1 md2 using md0 md1 Yes this will work, dm-multipath and mdraid use different subsystems. Configure open-iscsi to log into the two targets with two sessions each, setup the dm-multipath to arrange the sessions as either a round-robin or fail-over, then create a mdraid RAID1 out of the two multipath targets (use their multipath identities not their raw identities). There may be timing issues on system shutdown/startup, so test that fully and tweak it until it starts up properly without requiring a resync. -Ross