[Ocfs2-users] lvm2 not cluster aware - okay, so how should I stripe my LUNs?

[Fabio Corazza]

Brian Long wrote:
> I don't believe anything included in RHEL is supported across clusters
> for software RAID.  This means LVM and MD are out of the picture.

This is incorrect, I'm running EVMS 2.5.5 with Heartbeat 2.0.7 under
RHEL4.4 and it works pretty well. I've created filters under EVMS to
manage just the emcpower* devices, created a cluster container, and
created LVM2/EVMS volumes on top of it. In this way the EVMS devices are
accessible from both the nodes.

> Oracle only supports RAW devices, OCFS2 filesystems (one filesystem per
> SAN LUN) or ASM.  They also support Red Hat GFS, but only if you use
> external locking (GLM).  For a 4-node RAC cluster, you'd need 7 nodes (3
> dedicated to locking).  This is because Oracle insists that none of the
> RAC nodes participate in the GLM locking.  I believe Oracle may be
> certifying DLM, the newer lock manager in GFS, but I'm not sure.

Some people is using OCFS2 for general purposes, so any implementation
that uses RAC's components is out of the picture.

> Either way, GFS is an added cost on top of RHEL, but it includes RHCS
> and RHCS has cluster-aware LVM (I believe).

If possible, I suggest to stay away from RHCS.


-- 
Fabio Corazza - Engineering
NewBay Software, Ltd.
Wilson House, Fenian Street, Dublin 2, Ireland
Phone: +353 1 634 5490 - e-mail: fabio at newbay.com