RHCS

[Barry Brimer]

> I have some questions:
> - What is the difference between Redhat cluster suite and other open source
> HA

I have not compared RHCS to other open source HA systems

> - What is a cluster manager ?Is this the same as Cluster suite?

A cluster manager is one piece of software included in a cluster suite.

> - Can I implement a server cluster using cluster suite without having a
> shared external disk if the services do not need to share the data?

I believe this could be accomplished, provided you use lock_dlm in RHCS

> - if i want to implement RHCS on 2x nodes to use the external storage, what
> are the requirmnts for the SAN switch and SAN storage in case i go for
> External .Fiber chaneel storage

You must simply have FC cards that have driver support for your OS.  You 
must also have a fencing mechanism (method of abruptly rebooting a 
non-working node, to ensure that the non-working node can not come back to 
life and cause data corruption) which *can* be done through your SAN 
switch, in which case I would look at the different fencing agents in 
RHCS.  When available, I prefer a fencing mechanism like HP ILO, Dell 
Drac, or a network power switch.  I have never used I/O fencing with a SAN 
switch.

> - what about GFS license?

GFS (when used in a cluster) requires RHCS.  If you don't intend to share 
a disk between your nodes, GFS is not needed.  That being said, Red Hat 
provides a copy of RHCS with every copy of GFS.  GFS and RHCS are 
available under the GPL and with support from Red Hat.

> - If I want to use load balancing , can I use the RH cluster suite.

Yes.  RHCS includes lvs (linux virtual server) with the Piranha 
management/configuration tool.  It even supports having a failover load 
balancer.


> - Can some one guide me the minimum hardware requirement for the cluster
> suite?

It more depends on what you actually intend to do with it.  I use RHCS on 
HP intel hardware.  Nothing special.  If the hardware is robust enough to 
run your application(s) it shouldn't take much more to run RHCS as well.

> - Am thinking as a second option to use Hardware Load balancer form juniper
> or cisco to resolve the issue of cluster.

I am about to put in a pair of RHCS/lvs load balancers to replace a 
hardware load balancer.  It will give me redundancy and flexibility at 
commodity prices.

HTH,
Barry