chuck.hamilton (2/10/2014)
With SQL and AO, give me a scenario where some shared storage goes offline and it renders your data unavailable.
I never said it did, you want to review my initial response. I have pointed out that bringing an FCI into an AO group still has a dependency on shared storage and introduces a SPOF. AO does help to protect, but it's important to get the cluster quorum configuration correct from the outset
chuck.hamilton (2/10/2014)
If the quorum disk goes offline, who cares?
If your cluster has no shared storage how do you manage to have a quorum disk witness?
Unless your cluster is "same site" and has access to shared storage, you should use an alternative quorum configuration (based on your site config).
chuck.hamilton (2/10/2014)
At worst the cluster loses quorum and the default behavior is to leave all resource groups in the cluster running. They simply remain frozen on whatever node they were on until quorum can be reestablished and the cluster service can be restarted on all the nodes. In the meantime, the AO listener switches connections over to a replica in a matter of milliseconds - automatically.
Erm no, what I think you're describing here is a loss of multiple nodes resulting in the cluster going offline, correct? If this happens the listener will not be able to failover since it's a cluster resource.
Now, clustering under Windows 2012 has a new HA protection feature called "Dynamic Node Weight Configuration", this feature will balance out the quorum votes to account for a graceful shutdown of multiple nodes. The problem is, this will not protect against a disaster or sudden outage. I'll cover more of the cluster requirements in Part 2.
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