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

HAWKER, Dan dan.hawker at astrium.eads.net
Wed Sep 13 08:25:08 UTC 2006

> > 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
> > 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
> > structure away.
> > Am I correct in this assumption, or does GFS/RHCS need to use CLVMD in
> > 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.

>I think one of the big things is naming - ensuring that the device name
>is always the same on all nodes in the cluster - regardless of any
>devices added/changed/removed.  If you can do that, in addition to
>storage management, then there is probably no need to involve LVM
>(cluster or not).  If you plan to use LVM on top of the storage device,
>then you must use clvmd.
> brassow

Thanks for the replies. So, the decision is purely a matter of policy rather
than any technical reasons.

Didn't think of the possibility of extending the cluster storage by
utilising CLVM. Makes sense, nice feature, that may make me use CLVM anyway.

Guess I'll have a think and make a decision.

Thanks again


Dan Hawker
Linux System Administrator


This email is for the intended addressee only.
If you have received it in error then you must not use, retain, disseminate or otherwise deal with it.
Please notify the sender by return email.
The views of the author may not necessarily constitute the views of Astrium Limited.
Nothing in this email shall bind Astrium Limited in any contract or obligation.

Astrium Limited, Registered in England and Wales No. 2449259
Registered Office: Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2AS, England

More information about the Linux-cluster mailing list