VCS global cluster configuration

Hello,

WAC resource is an ICMP connection between your two sites which works on IP address. ICMP packets are sent between two sites to check the "ALIVE" status of DR site.

Couple of bullet points to remember

Each VCS cluster must have a valid virtual IP address to be used as the clusters ‘ClusterAddress’ for ICMP and WAC communication. This address should be made highly available such that it is always configured on one node in the VCS cluster (normally by adding the address to the ClusterService service group)

Each VCS clusters ‘ClusterAddress’ should be resolveable to a host name (i.e. using DNS for example)

You can use "Add cluster" wizard to configure global cluster, this will require the ClusterAddress IP address of all clusters being added to the GCO cluster.

an e.g main.cf is like

remotecluster test20001 (

        ClusterAddress = "10.12.251.191"

        )

heartbeat Icmp (

        ClusterList = { test20001 }

        AYATimeout = 30

        Arguments @test20001 = { "10.12.251.191" }

        )

Hope this helps

G

Yes heartbeat IP address and ClusterIP address are normally the same so cluster ips should be set in 4 places:

1. Global cluster heartbeat
2. ClusterAddress attribute in cluster definition
3. Address attribute of IP resource in ClusterService group
4. remotecluster - here you specify cluster IP of remote cluster, not local cluster

I think technically you could use a separate IP for the heartbeat, but I can't think of a reason why you would want to do this.  If you have a separate independent link across sites, then I believe you can add a second global cluster heartbeat if you wanted

I believe cluster information is transfered over the cluster IP addres and heartbeats over the heartbeat address, which, as above, are normally the same IP, so provide the same functionallity as GAB, but is completely separate from GAB.

Mike

Hello,

Yes you are right, if an incorrect IP is assigned or somehow the two cluster IP addresses can't communicate to each other, the status of remote cluster won't be known to cluster. Ideal state of heartbeat will be displayed as "Alive" in hastatus -sum output which won't be case in afore said situation.

About the resolution of hostname to IP, I don't believe its mandatory but its good to have as it can help to mark easy names for server , sites or IP addresses .. Only putting IP addresses will make it difficult to remember.

G