6/08/2009

Disaster Recovery setup


I'm trying to setup a Redhat Cluster that could be site disaster proof.

To illustrate this, see the diagram.

The nodes would service databases instances (not in a RAC fashion), or NFS services, each service running on one node at a time.

The principles would be to use Clustered LVM (CLVM) and LVM mirroring on top of it (though it does not yet support online resizing, and it still needs a 3rd device to carry the metadata).

The main question about this kind of setup (with RHCS) is about the quorum in case one of the 2 sites were to go down, the other site not having anymore the majority, the whole cluster would go down.

We are already managing a few hundreds of clusters this way using non RH (HP ServiceGuard) clustering software and it handles the site loss scenario by provinding a "out-of-cluster" tie-breaker on a 3rd site which guarantees a split-brain proof setup.

3 comments:

Karlhat said...

Hi,

CLVM, GFS2 and CMIRROR are not supported over multi-site cluster with RHCS; however RedHat recomend LVM mirror between 2 SAN, and to use a third node in second site, but I really looking for solution with DRBD+RHCS, in RHEL6 rgmanger and DRBD are integrated. :)

regards

Carlos Alberto Ramirez

karlox@linuxmail.org

Karlhat said...

Hi,

CLVM, GFS2 and CMIRROR are not supported over multi-site cluster with RHCS; however RedHat recomend LVM mirror between 2 SAN, and to use a third node in second site, but I really looking for solution with DRBD+RHCS, in RHEL6 rgmanger and DRBD are integrated. :)

regards

records management company said...

This seems interesting, would you say it'll be good for small businesses as well? Lately I've been hearing about more and more businesses getting caught off-guard and just losing all of their data. What a nightmare!