Tag Archives: VMDK

PowerCLI and VVols Part IV: Correlating a Windows NTFS to a VMDK

My last post in this series was about getting a VVol UUID and figuring out what volume on a FlashArray it is. But what about the step before that? If I have a guest OS file system how do I even figure out what VMDK it is?

There is a basic option, which can potentially be used, which is correlating the bus ID and the unit ID of the device in the guest and matching it to what VMware displays for the virtual disks.

But that always felt to me as somewhat inexact.  What if you accidentally look at the wrong VM object and then do something to a volume you do not mean to? Or the opposite?

Not ideal. Luckily there is a more exact approach. I will focus this particular post on Windows. I will look at Linux in an upcoming one. Continue reading PowerCLI and VVols Part IV: Correlating a Windows NTFS to a VMDK

VMware Storage Capacity Reporting Part I: VMFS and Thin Virtual Disks

Storage capacity reporting seems like a pretty straight forward topic. How much storage am I using? But when you introduce the concept of multiple levels of thin provisioning AND data reduction into it, all usage is not equal (does it compress well? does it dedupe well? is it zeroes?).

This multi-part series will break it down in the following sections:

  1. VMFS and thin virtual disks
  2. VMFS and thick virtual disks
  3. Thoughts on VMFS Capacity Reporting
  4. VVols and capacity reporting
  5. VVols and UNMAP

Let’s talk about the ins and outs of these in detail, then of course finish it up with why VVols makes this so much better.

Continue reading VMware Storage Capacity Reporting Part I: VMFS and Thin Virtual Disks

Do thin VVols perform better than thin VMDKs?

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?