Hi folks. We are just wrapping up a project similar to this, getting ready to go live. It’s a 2012 R2 Cluster running a SQL 2012 role.
Our design for the DR is slightly different though. We have a 2 node High Availability Cluster in the Prod site so they failover from one to the other if needed, and a 3rd DR node at the remote DR site. However, the DR node will never become active on it’s own. We have it set up for manual failover to DR from Prod. Our config uses a Disk witness, but it’s a clustered resource vs a share. In our discussions with MS, for our configuration, they said it wasn’t an issue either way. We also removed the nodeweight (vote) for the DR server as part of the manual failover setup we’re using. Not sure if that helps, but thought I would share ;) Don K From: [email protected] [mailto:[email protected]] On Behalf Of Miller Bonnie L. Sent: Monday, August 18, 2014 3:29 PM To: [email protected] Subject: RE: [NTSysADM] Clustering question - 3 node cluster across 2 sites, and a quorum I see the confusion, but I think the drawing is misleading/wrong. The whole section is prefaced with this Note: “In the illustrations, for all configurations other than Disk Only, notice whether a majority of the relevant elements are in communication (regardless of the number of elements). When they are, the cluster continues to function. When they are not, the cluster stops functioning.” And read the first comment at the bottom as well. The problem with the idea of this configuration is that you can end up in a split cluster scenario. What happens if the link between Primary and DR is severed, but the link between primary and 3rd is up (or severed), and the link between DR and 3rd is up? Your physical topology may not allow for that, but Microsoft does. In that case, by this logic, both your DR site and your main site would each think they have quorum and would individually continue to run. Rather than allowing that scenario, the cluster will shut down. From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Michael Leone Sent: Monday, August 18, 2014 12:42 PM To: [email protected]<mailto:[email protected]> Subject: Re: [NTSysADM] Clustering question - 3 node cluster across 2 sites, and a quorum On Mon, Aug 18, 2014 at 3:32 PM, Miller Bonnie L. <[email protected]<mailto:[email protected]>> wrote: > I would say no then, as "Node and File Share majority" means MORE than half > of the voting members need to be online: > > http://technet.microsoft.com/en-us/library/cc770620(v=ws.10).aspx He says that < http://technet.microsoft.com/en-us/library/cc731739.aspx > says you can. Hence his question ... Specifically: Node and File Share Majority Quorum Configuration In a cluster with the Node and File Share Majority configuration, the nodes and the file share witness are counted when calculating a majority. This is similar to the Node and Disk Majority quorum configuration shown in the previous illustration, except that the witness is a file share that all nodes in the cluster can access instead of a disk in cluster storage. [Cluster with Disk Only quorum configuration] In a cluster with the Disk Only configuration, the number of nodes does not affect how quorum is achieved. The disk is the quorum. However, if communication with the disk is lost, the cluster becomes unavailable. So if the 2 nodes in PrimarySite went down, but the node in DR-Site stayed up, and the Witness disk at ThirdSite stayed up (and in communication with DR-Site), then that diagram says the cluster stays up. That's what he's trying to confirm.
