Migrating VMDKs or virtual mode RDMs to VVols is easy: Storage vMotion. No downtime, no pre-creating of volumes. Simple and fast. But physical mode RDMs are a bit different.
As we all begrudgingly admit there are still more than a few Raw Device Mappings out there in VMware environments. Two primary use cases:
- Microsoft Clustering. Virtual disks can only be used for Failover Clustering if all of the VMs are on the same ESXi hosts which feels a bit like defeating the purpose. So most opt for RDMs so they can split the VMs up.
- Physical to virtual. Sharing copies of data between physical and virtual or some other hypervisor is the most common reason I see these days. Mostly around database dev/test scenarios. The concept of a VMDK can keep your data from being easily shared, so RDMs provide a workaround.
Continue reading Moving from an RDM to a VVol
Yes. Any questions?
Ahem, I suppose I will prove it out. The real answer is, well maybe. Depends on the array.
So debates have raged on for quite some time around performance of virtual disk types and while the difference has diminished drastically over the years, eagerzeroedthick has always out-performed thin. And therefore many users opted to not use thin virtual disks because of it.
So first off, why the difference?
Continue reading Do thin VVols perform better than thin VMDKs?
I have been talking a lot about Virtual Volumes (VVols) lately with customers and when I describe what they are a frequent response is “oh so basically RDMs then?”. ..
…ugh sorry I just threw up in my mouth a bit…
The answer to that is an unequivocal “no” of course, but the question deserves a thorough response.
So first let’s look at how they are the same, then let’s look at their differences. And not just how they compare to RDMs, but also VMDKs as you traditionally know them.
Continue reading Comparing VVols to VMDKs and RDMs
Virtual Volumes change quite a lot of things. One of these is how your storage volumes are actually connected. This change is necessitated for two reasons:
- Scale. Traditional ESXi SCSI limits how many SCSI devices can be seen at once. 256 in 6.0 and earlier and 512 in 6.5. This is still not enough when every virtual disk its own volume.
- Performance. Virtual Volumes are provisioned and de-provisioned and moved and accessed constantly. If every time one of these operations occurred a SC SI rescan was required, we would see rescan storms unlike this world has ever witnessed.
So VMware changed how this is done. Continue reading Virtual Volumes: VVol Bindings Explained
Virtual Volumes provide a great many benefits, some large, some small. Depending on the VM, recovering a deleted VM could be either of those.
With traditional VMFS, once you have selected “delete from disk” restoring that VM could have been a process. Either restoring from backup or hoping you had a snapshot of the VMFS on the array. Either way, you are probably going to incur data loss, as the last backup or snapshot is unlikely to be from the time right before the deletion.
Let me be VERY clear here. Regardless to the rest of this post, I am not saying once you move to VVols you do not need backup! You absolutely still do. VVols just give you a nice way to do an immediate recovery of the latest point-in-time without having to lose anything, assuming your array support it.
“Wait, did you say delete VM “AD” or VM “80”?”
“Um… definitely not AD that’s our active directory…”
Continue reading Recovering a Deleted Virtual Machine with VVols
I posted a few months back about ESXi queue depth limits and how it affects performance. Just recently, Pure Storage announced our upcoming support for vSphere Virtual Volumes. So, this begs the question, what changes with VVols when it comes to queuing? In a certain view, a lot. But conceptually, actually very little. Let’s dig into this a bit more.
Continue reading Queue Depth Limits and VVol Protocol Endpoints
This is a blog post I have been waiting to write for quite some time. I cannot even remember exactly how long ago I saw Satyam Vaghani present on this as a concept at VMworld. Back when the concept of what is now called a protocol endpoint (more on that later) was called an I/O Demultiplexer. A mouthful for sure. Finally it’s time! With pleasure, I’d like to introduce VVols on the FlashArray!
Continue reading Introducing vSphere Virtual Volumes on the FlashArray
This is all very exciting for me, finally able to really start blogging about VVols in earnest. As you may or may not be aware we (Pure Storage) currently have our VVol implementation in beta. So I can finally start digging into some VVol work. Not going to get into implementation details just yet, but instead a quick walkthrough of importing a VVol snapshot with PowerCLI.
First, enjoy a poorly photoshopped Back To the Future reference:
Continue reading Importing a VVol Snapshot with PowerCLI