There have been a number of queries around Virtual Volumes (VVols) and replication, especially since the release of KB article 2112039 which details all the interoperability aspects of VVols. In Q1 of the KB, the question is asked “Which VMware Products are interoperable with Virtual Volumes (VVols)?” The response includes “VMware vSphere Replication 6.0.x”. In Q2 of the KB, the question is asked “Which VMware Products are currently NOT interoperable with Virtual Volumes (VVols)?” The response includes “VMware Site Recovery Manager (SRM) 5.x to 6.0.x” In Q4 of the KB, the question is asked “Which VMware vSphere 6.0.x features are…
In some previous posts, I highlighted how VVols introduces the concept of “undo” format snapshots where the VM is always running on the base disk. I also mentioned that this has a direct impact on the way that we do snapshots on VMs that support VSS, the Microsoft Volume Shadow Copy Service. But before getting into the detail regarding how VVols is different, it’s worth spending some time understanding whats going on when VSS is called to quiesce applications when a traditional snapshot is taken. If you try to research this yourself, you’ll find that there is very little information…
There is a new snapshot format introduced in VSAN 6.0 called vsanSparse. These replace the traditional vmfsSparse format (redo logs). The vmfsSparse format was used when snapshots of VMs were taken in VSAN 5.5, and are also the format used when a snapshot is taken of a VM residing on traditional VMFS and NFS. The older vmfsSparse format left a lot to be desired when it came to performance and scalability. This KB article from our support team, indicating that no snapshot should be used for more than 72 hours, and snapshot chains should contain no more than 2-3 snapshots,…
I first encountered Rubrik at this year’s Partner Exchange (PEX) 2015 in San Francisco. They had some promotional flyers made up labeled “Backup Still Sucks”. I guess a lot of people can relate to that. I had a chat with Julia Lee, who used to be a storage product marketing manager here at VMware, but recently moved to Rubrik. Rubrik’s pitch is that customers are currently stitching together backup software with backup storage in order to backup their virtual infrastructures – there is no seamless integration. Rubrik’s primary aim is backup simplicity – they want to provide a “time machine”…
Well, I got so many questions about my previous articles on a new way of doing snapshots with VVols that I decided to take the time and get even deeper into their behaviour. In this setup, I take a Windows 2008 Guest OS running in a virtual machine deployed on an NFS datastore, and I compare it to an identical VM deployed on a VVol datastore. This is purely from looking at how we do snapshots. Remember with VVols, snapshots always run on the base disk, compared to the traditional way of doing snapshots where the VM always run on the…
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…