I learnt something interesting about Virtual Volumes (VVols) last week. It relates to the way in which snapshots have been implemented in VVols. Historically, VM snapshots have left a lot to be desired. So much so, that GSS best practices for VM snapshots as per KB article 1025279 recommends having on 2-3 snapshots in a chain (even though the maximum is 32) and to use no single snapshot for more than 24-72 hours. VVol mitigates these restrictions significantly, not just because snapshots can be offloaded to the array, but also in the way consolidate and revert operations are implemented.
There are a couple of key concepts to understanding Virtual Volumes (or VVols for short). VVols is one of the key new storage features in vSphere 6.0. You can get an overview of VVols from this post. The first key concept is VASA – vSphere APIs for Storage Awareness. I wrote about the initial release of VASA way back in the vSphere 5.0 launch. VASA has changed significantly to support VVols, with the introduction of version 2.0 in vSphere 6.0, but that is a topic for another day. Another key feature is the concept of a Protocol Endpoint, a logical I/O…
I’m a bit late in bringing this to your attention, but there is a potential issue with VASA storage providers disconnecting from vCenter resulting in no VSAN capabilities being visible when you try to create a VM Storage Policy. These storage providers (there is one on each ESXi host participating in the VSAN Cluster) provide out-of-band information about the underlying storage system, in this case VSAN. If there isn’t at least one of these providers on the ESXi hosts communicating to the SMS (Storage Monitoring Service) on vCenter, then vCenter will not be able to display any of the capabilities…