One of the major advantages we have seen with VVols is making a virtual disk a first class citizen on the array. We can restore, copy, replicate them (and their VMs) as storage objects were meant to be restored, copied, replicated etc.
Though one thing about virtual disks is that by default–they are not first class citizens in vSphere, VVols or otherwise. To create one, it has to be associated with a VM.
To retrieve one in PowerCLI (for example) get-harddisk requires a datastore or a VM to return a result:
This post will be about managing one-off snapshots with VVols on the FlashArray with PowerCLI.
One of the still semi-valid reasons I have seen DBAs say “I dont want to virtualize because…” Is that they have simple snapshot/recovery scripts for their physical server that allows them to quickly restore DBs from snapshots. Doing this on VMFS requires A LOT of coordination with the VMware layer.
So they tell the VMware team–“okay I will virtualize but I want RDMs”. Well the VMware team says “well we’d rather die”
…and around in circles we go…
VVols provides the ability to provide this benefit (easy snapshot stuff) but still get the benefits of VMware stuff (vMotion, Storage vMotion, cloning, etc) without the downside of RDMs.
A few months back I was reviewing our VMware training for our field (and after some direct feedback) realized it wasn’t really doing what our field needed. It was too nuts and bolts technical–which isn’t really what was needed by the masses. There was more of a desire to understand the value of the VMware product, the value of the integration and the value that we as Pure can bring to it.
The ones that wanted/needed more technical training could get that as needed.
In short, what they wanted to be able to do was have the “I’m staffing a booth at a conference and someone asks me about vRealize Orchestrator”. Not being an expert in the product, how to do I quickly understand the value, so I know if I am chasing the right product/solution and I should inquire further.
One of the first technical benefits users can enjoy around VVols is the use of snapshotting. Snapshots created through VMware of VMs have always been a point of contention which as severely limited their usability (see a post I did around the performance impact of them here).
With VVols, when you right-click on a VM and choose take snapshot, VMware does not create the performance-impacting delta VMDK files that were traditionally used, but instead VMware entirely offloads this process to the array. So the array creates the snapshots and VMware just tracks them.
But since VMs are now a collection of individual volumes on the array (a VVol is just an array volume) you can also snapshot and restore individual virtual disks as well directly on the array.
I wrote a blog post a year or so ago about ESXi and storage queues which has received a lot of wonderful feedback (thank you!!) and I eventually turned it into a VMworld session and other engagements:
So in the past year I have had quite a few discussions around this. And one part has always bothered me a bit.
In ESXI, there are a variety of latency metrics:
GAVG. Guest average. Sometimes called “VM observed latency”. This is the amount of time it takes for an I/O to be completed, after it leaves the VM. So through ESXi, through the SAN (or iSCSI network) and committed to the array and acknowledged back.
KAVG. Kernel average. This is how long an I/O is spending in the ESXi kernel. If this is anything but zero, there is some kind of bottleneck (often a maxed out queue)
DAVG. This is how long it takes for the I/O to be sent from host, through the SAN and to the array and acknowledged back.