Setting up Linux Quorum Server

[IT_2007]

Need some help to setup Red Hat Linux Quorum Server in two node HP-UX cluster environment.

Environment:
A) 2 node cluster and 1 node at each data center under same VLAN.
B) Total of 3 clusters running with 2-node clusters one for Prod, one for Dev and one for QA.
C) Can setup Red Hat Linux server as Quorum at 3rd Datacenter but don't have same VLAN available at 3rd Datacenter.

What do I need to start with? As per Quorum server documentation, I can setup Linux box as quorum server in 3rd Datacenter. Should I make it as a package or without package also can be done?

If anybody already done with installations, please throw some guidelines.
Please help me.

thanks,
IT

[IT_2007]

forgot to ask about existing lock disk. Do I need to unconfigure / remove existing lock disk from the running cluster?

or

can I use cluster lock and quorum server together?

[melvyn burnard · Accepted solution]

Well you were given answers in your previous thread
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1087036

But to answer you, it is up to you to decide whether to have it as a package in another SG cluster or not, it does NOT have to be on the same subnet, and no you cannot have both a QS and a cluster lock configured in a cluster, one or the other is your choice.

[IT_2007]

Melvyn,

Thanks for reply. I read documentation and didn't give much installation steps to proceed further.

1. If I don't configure quorum server as package and if quorum server dies while cluster running, what happens to the cluster? Document says cluster will be up and running even if quorum server dies/reboots (only if it is configured as package not as service?)

2. Is there any documentation provides detailed installation steps for exisiting cluster environment?

Thanks in advance.

[Mike Chisholm]

QS can be a on a standalone linux box without Serviceguard. As long as all nodes in all clusters have IP access to the QS box, you are OK, you do not have to have link level access.

If the QS goes down, the clusters will continue to run, but they will log periodic messages in syslog.log(/var/log/messages on linux) that they cannot reach the quorum server. If there is a cluster reformation and the QS is unavailable, then you risk a split-brain cluster and this is very bad, therefore it is in your best interest to fix the QS as quickly as possible if it goes down. This is the reason some people put the QS as a package in a cluster.

Note that a QS cannot serve as a QS for it's own cluster.

As far as setup goes, the steps are clearly documented in the release notes for both HP-UX and linux. Please take a look through http://docs.hp.com/en/B8467-90031/B8467-90031.pdf specifically pages 11 through 17. If you are not configuring the QS as a package, then just ignore the section "Creating a Package for the Quorum Server". Hope this helps.

[Mike Chisholm]

And in case I'm not understanding what you mean by "installation", if you mean how do you change a cluster from using a lock disk to use QS instead, you do this:
1) halt the cluster
2) edit the cluster ASCII file and comment out the lock disk entries
3) uncomment the QS_* entries and fill in the appropriate values
4) run cmapplyconf -C
5) start the cluster
6) use cmviewcl -v to verify QS status

You must halt the entire cluster to change the lock methodology from disk/lun to QS.

[IT_2007]

Thanks to Mike and Melwyn. Now I can start working on this.

Thanks a bunch.

[IT_2007]

since I don't have same subnet available for Quorum server, can I create a package for QS?

Have 3 clusters running each with 2 nodes. Planning to install two quorum servers and create packages in each cluster pointing to these QS servers. Hope it is possible.

[melvyn burnard]

yes it is, when setting up a cluster, you supply the QS hostname or ip address using the -q option to cmquerycl

You may also want to take a look at this document if you want cross cluster quorum servers:
http://docs.hp.com/en/6626/XclusQS.pdf

[IT_2007]

Melvyn,

I read Cross cluster Quorum server configurations and didn't understand in page 2 says:

HP recommends in the one of the following ways:

A two (or more) node cluster using a cluster lock disk, that has a Quorum Server package on it.

does this mean that I can create a QS package to monitor along with lock disk and this would avoid split brain stituation? Would you please see the doc and comment on it?

thanks.