Global Cluster Setup
Planning to seup a lab before I create the environment on Production.
This is our Lab setup for Global Clustering.
4 VMs ( Centos 6.1)
2 Nodes cluster
One pair act as PRO and other pair will act as DR.
We will use VVR for replica.
When we create remote cluster(DR), do we need to keep the same cluster name, service group name and resource name?
Service groups which you configure as global service groups need to have the same name in each cluster.
The cluster names should be different.
I don't think it matters if resource names are the same
Mike
Hello,
Service group names to be very much same because they would be part of global configuration. Consider it like a simple service group in local cluster where service group names must be same, can u keep the service group name different in local cluster ? answer would be no because VCS understands it is same group while the systemlist attribute defines which systems this group can failover.
The only difference here in GCO is the cluster are site separated, though once service group is part of global configuration, VCS will treat this as one service group & systemlist is now scaling beyond datacenters to remote cluster
A snippet from VCS Admin guide about Global Service Groups
Global service groups
A global service group is a regular VCS group with additional properties to
enable wide-area failover. The global service group attribute ClusterList defines
the list of clusters to which the group can fail over. The service group must be
configured on all participating clusters and must have the same name on each
cluster. The Global Group Configuration wizard provides an easy interface to
configure global groups.
See“Administering global service groups” on page 516.
VCS agents manage the replication during cross-cluster failover.
See “VCS agents to manage wide-area failover” on page 471.G
Note: non-global service groups do not need to have the same names (ie: groups that will not failover between clusters can have different names) - just the global service groups (that do failover between clusters) need to have the same names for the reasons outlined by Gaurav above.
Cluster names must be unique within each global cluster; system and resource names need not be unique across clusters. Service group names need not be unique across clusters; however, global service groups must have identical names.
Suppose you have 2 clusters at production and dr and 2 apps called app1 and app2 - then your clusters names are typically based on the location so you could call prod_clus and dr_clus or base names on geographic location.
The service groups names are normally based on the application name, like app1_sg and app2_sg and your application should be the same from a client point of view whether it is running at prod_clus or dr_clus and hence it is logical to use the same name and this is enforced as what makes a service group global is that you specify the ClusterList service group attribute which defines the clutsters the group can run on and there is nowhere to specify the remote service group name so it must be the same.
Resource names are generally the same, as the application would normally start with the same process names and use the same mount points so it makes sence to use the same resource names for these, but prod and dr might use different hardware so your NIC resources may have different names if you base your NIC resource names on the network device and this is different between clusters.
Mike
Note it is a similar case for VVR:
For the diskgroup names, by default, it is assumed you have used the same diskgroup name, but you can use different diskgroup names if you want, but the volume names must be the same for each diskgroup - see extracts from vradmin manpage for addsec option:
The addsec command creates a Secondary RVG in the disk group with the same name as the Primary disk group. If required, you can use the option -sdg diskgroupto specify a different disk group on the Secondary.
The addsec command requires that the data volumes and SRL must exist on the Secondary with the same names
Mike
Hello,
you can switch the service group which is configured as global group, there could be one group, there could be many ..
Resources like WAC or cluster heartbeat as explained above are part of clusterservice group which will anyways exist & will be online on remote cluster, so you don't need to switch that ..
I would recommend you to run through the guides to build concepts ,this will also clear lot of your queries..
https://sort.symantec.com/public/documents/sfha/6.1/solaris/productguides/html/vcs_admin/ch17s04s04.htm
G
If switching a group manually, you can ONLY switch one global group at time - there is no "switch all global groups" option.
If your cluster fails, then you get a "cluster failure" alert which gives you a list of the global service groups and you can select all, or just select the groups you want to fail over.
Mike
You can check if ClusterList attribute is populated:
hagrp -display -attribute ClusterList
or in the java GUI there is a "3d" circle around the group on the left pane.
Mike
