We have recently converted an Active/Passive cluster to an Active/Active cluster (SQL2005). I understand that if one of the nodes fails, the remaining node will have to carry all of the load. I'd like to run each of the Active nodes at better than 45% utilization. But, I'm concerned about the consequences of this if one of the nodes fails. For instance, if I plan for each node to run at 60% utilization, logically, a failure would result in a single node at 120% utilization. NOT GOOD.
Is there a way to restrict the resources available on the remaining node following a node failure? Sort of a dynamic resource governor...
Let's say no governor is available. If my 120% utilization fails to a single node, will it crash or just cause the applications to experience slower performance? I'd be fine with some degraded performance, but not a crash.
Thanks for your insights!
1) higher levels of windows server come with a resource management capability
2) enterprise SQL Server 2008+ also comes with a resource governor
3) outside of those two, you 'COULD' set processor affinity at the instance level after a failover, but I would be very leery of that solution.
I don't think any of those solutions have the ability to throttle IO though (could be wrong about windows server one).
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru at GMail