[Linux-cluster] CLVMD - Do I need it???

[Lon Hohberger]

On Tue, 2006-09-12 at 09:25 +0100, HAWKER, Dan wrote:
> 
> Hi All,
> 
> Have an EMC SAN unit on the way. I plan to use it as the central store for a
> couple of servers setup as a cluster, using GFS. As the SAN unit can handle
> all of its own Logical Volume management natively, I presume I don't have to
> use/implement CLVMD and hence can cut one layer of complexity in the disk
> structure away.

> Am I correct in this assumption, or does GFS/RHCS need to use CLVMD in its
> configuration???

You don't need CLVM if you intend to use the internal array tools, but
it's a "nice to have" thing.  After all, we've had GFS (and simple
failover, for that matter) for a few years -- while CLVM is a relatively
new technology.  Some SANs can do this internally too, of course.

For example, if you had CLVM and you add another array, I'm pretty sure
you could use CLVM to extend an existing logical volume on to the second
array while the cluster is running.

-- Lon