Unbalanced Cluster in RSXi

[haris2887]

Hello all.

I have a question regarding clustering,

I am aware that it is best practise to have all the hosts in the cluster with the same specs but what if they are not.

What if there is a memory difference or an odd number of hosts eg 3 hosts.

Basically we have a DR site with one host there is also a replicates SAN on both sides not pictured.

I am happy to run at limited capacity during a failure, EG we have 4 domain controllers , 4 DFS file servers. 4 Exchange CAS servers. In the event of a failure i am happy to only run 1 DC and 1 DFS server and Maybe 2 Exchange servers.

The DR site also has its on Virtual Machines running.

Is the question as simple as, I have to make sure there is enough slot size in the DR site to accommodate for the fail over ?

What if I also want DRS, that means the server in the DR site has more resources and hence runs more of the virtual machines hence decreasing the available slots for VM for Primary site to Fail-over to the DR site.

any thoughts ?

Here is a picture.

[JPM300 · Accepted solution]

What are you using to failover the hosts to the DR site?  Are you using SRM or are you just manually bringing up the VM's from the SAN replication in the event of a failure?

Is your Main DC and DR DC on a flat network?

If you are using SRM and failover to the DR site the VM's will come online and then follow the instructions set by the DR Cluster, (HA, DRS, Slot size, ect)  I usally don't set my failover settings to 1 host as I don't like dealing with slot sizes and having to constantly monitor them and or re-configure them if 1 VM punches out the slot size.  So I usually use the % setting instead and set my DR site to 10% or 25% whatever your conformable with.  Once everything is failed over and powered on DRS will start moving things around as needed.  Also if you use SRM you do have the ability to specifiy which hosts you want things to start on if you so desire and or have the ability to run scripts at the end of the SRM jobs to do any other things required.

I hope this has helped,

If you have any other questions please let me know,