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vSphere 6.0 Storage Features Part 3: MSCS Improvements

OK – not storage improvements per-se, but I got into the habit of documenting our Microsoft Clustering Services (MSCS) improvements some time back, and habits die-hard. Many of our customers continue to run Microsoft Clustering Services (MSCS) on top of vSphere. This is well-recognized, and VMware continues to improve and add features around this for our customers. vSphere 6.0 is no different, with a selection of improved functionality around MSCS on vSphere.

1. vMotion of MSCS nodes using pt-RDMs

Yes, it’s finally here. The ability to vMotion virtual machines with pass-thru raw device mappings (RDMs), and that includes virtual machines that are being used as nodes in MSCS. (Pass-thru mode is also referred to as physical compatibility mode). Of course, MSCS is about the only thing that uses RDMs at this stage, and we would recommend that you avoid using them if at all possible. But since MSCS still places a SCSI reservation on the actual disk as part of its tie-breaking procedure when a failure occurs, the use of RDMs is still necessary so that the SCSI reservation can go all the way down to the disk (and not be converted to a file lock, which is what happens with VMDKs and non-pass-thru RDMs). Lot of changes were made to the various storage layers in the VMkernel to checkpoint/restore SCSI-3 reservations during a vMotion. Awesome stuff!

2. MSCS and IPV6 inter-op

VMware has done a lot of work in vSphere 6.0 around IPv6. We can now deploy MSCS nodes running in VMs with IPv6.

3. PVSCSI support for MSCS

This has been a request I’ve heard a number of times. PVSCSI, or ParaVirtual SCSI Bus Adapters can provide even more performance than other virtual SCSI bus adapters in certain conditions/workloads. PVSCSI adapters are now supported as a virtual adapter for virtual machines that are configured as MSCS nodes.

4. Guest OS and Application Support

VMware now supports the following guest OS and applications with MSCS in vSphere 6.0:

5. Protect vCenter Server 6.0 with MSCS

I read this on a recent vSphere blog post. It seems that, amidst the initial confusion, vCenter Server 6.0 (and 5.5 U3) will now support the clustering of the vCenter Server using MSCS, in addition to the back-end database. It seems that there will be more information coming soon, and I’d recommend checking the vSphere blog regularly for updates.

A nice set of improvements in vSphere 6.0 around MSCS.

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