[Linux-cluster] any timeline for supporting software RAID?

[Jeff Wasilko]

On Wed, Jan 23, 2008 at 02:20:44PM -0500, Lon Hohberger wrote:
> On Tue, 2008-01-22 at 16:18 -0500, Jeff Wasilko wrote:
> > On Tue, Jan 22, 2008 at 03:59:47PM -0500, Christopher Hawkins wrote:
> > > If you don't need GFS... Then drbd + heartbeat is a good way to go if you
> > > want to mirror the local storage on each machine.
> > 
> > True, except Zimbra has explicit support for RHCS, and we'd be off
> > rolling our own solution with drbd + heartbeat....
> 
> As I recall, you can use LVM mirroring.  In recent versions of RHCS (4.6
> maybe?), there's an agent to handle assembly/disassembly of LVM
> (non-clustered) volume groups before/after failover.

Hi Lon!

Thanks for the info!

Could you point me to docs on the agent? I'm still very new to the product
and trying to figure out it if it'll work for us....

> If only one node is accessing the data at a time, maybe this would work
> for you. (Assumes, of course, you have a SAN)

Yup, we have a SAN. 

> With software RAID (or plain LVM), the general rule is:
> 
> Do not use a md set or LVM volume group on shared storage *unless* only
> one node ever assembles that volume-group / raid-set at a time.

Which would be the case when LUNs were being failed over from node
to node in an active-passive environment.

The docs all seem to flatly state that mirroring and cluster aren't supported.
Is this something that redhat's support organization is willing to support
at this point?

Thanks again!

-j