[Linux-cluster] Sanity Check

[Steven Dake]

On Tue, 2008-05-06 at 12:57 -0600, Brian D. Haymore wrote:
> I tried to send this yesterday but didn't see it on the list yet so I 
> apologize if this ends up being a duplicate.
> 
> 
> 
> 
> We have been starting to play with Cluster Suite as part of RHEL over 
> the past week.  Our needs, we think, are pretty basic.  However we have 
> not found enough information in the docs to help validate our plans as 
> being sane.  So for that I'm turning to the list in hopes someone can help.
> 
> What we are trying to do is simply have 3 servers attached to a SAN with 
> common disk storage.  By common storage I simply mean the SAN is zoned 
> so that all three servers can see this common storage.  We then want to 
> lvm, cluster lvm flag enabled, this storage such that we can create many 
> logical volumes.  Each of those LVs would have an ext3 file system on 
> it, implying only one server at a time will mount and use it.  Then we 
> can take the N LVs and distribute them out between the three servers in 
> a very fixed fashion.
> 
> So thus far we see that we need to have CMAN running as well as have 
> lvm2-cluster installed and having run `lvmconf --enable-cluster`.  Then 
> from system-config-lvm we created a cluster of our 3 servers.  We think 
> that is about all we need to do for this very crude initial setup.  This 
> is where we wanted to get some feedback if in fact this is an 
> acceptable, while overly basic, configuration.  Could someone offer any 
> feedback here?
> 
> We do realize that we are ignoring many of the key features of the 
> cluster setup where we could define these LVs and their file systems as 
> resourced as well as the services using them and have cman, rgmanager, 
> etc help build a more robust and polished setup.  We are in a time 
> crunch for now and need to get an initial setup going thus the above 
> question, then with time we hope to learn the other parts of the system 
> and then migrate things in a better direction.  Thanks for your time.
> 
> 

Your design should work fine although maybe not clearly defined in any
documentation as a use case.  If you have no need of shared storage for
the logical volumes, then there is no need for gfs.  You will need to
run lvm2 (clvmd) in clustered mode so that each node sees the logical
volume changes when any node makes a change.

check out the documentation section on

http://sources.redhat.com/cluster/wiki

you may find some information there that is helpful in your
configuration.

Regards
-steve