Martin Schwenke wrote: > On Tue, 30 Mar 2010 14:07:02 +0900, Kiyoshi Ueda <k-ueda@xxxxxxxxxxxxx> > wrote: > >> Why do you want to use dm-multipath on virtio block devices? > > For consistency rather than failover... :-) > > I'm using virtual machines to test a clustered NAS environment. The > production setup expects to see dm devices from dm-multipath. So I'm > using dm-multipath on virtio block devices to simulate use of > dm-multipath in a SAN environment. > megasas megasas megasas ... I posted a megasas HBA emulation for KVM a while back. Would solve your problem rather elegantly. But then you'd have to recompile KVM, at which point you could include the SCSI emulation as well ... > The RHEL 5.4 version of KVM doesn't contain a SCSI emulation, so the > only 2 choices for large numbers of block devices are virtio and > iSCSI. I'm trying to keep my options open for both of these. > > The fix for virtio block devices seems quite straightforward, so I > thought I would propose it. :-) > Problem is, though, that you don't have a unique ID for virtio devices. EG scsi_id and friends don't work here. And AFAIR there is no feature flag which would allow you do set one. How do you distinguish between, say, 2 virtio devices across 2 paths? Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@xxxxxxx +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Markus Rex, HRB 16746 (AG Nürnberg) -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
