Tag Archives: esxi

Understanding VMware ESXi Queuing and the FlashArray

So I am in the middle of updating my best practices guide for vSphere on FlashArray and one of the topics I am looking into providing better guidance around is ESXi queue management. This breaks down to a few things:

  • Array volume queue depth limit
  • Datastore queue depth limit
  • Virtual Machine vSCSI Adapter queue depth limit
  • Virtual Disk queue depth limit

I have had more than a few questions lately about handling this–either just general queries or performance escalations. And generally from what I have found it comes down to fundamental understanding of how ESXi queuing works. And how the FlashArray plays with it. So I put a blog post together of a use case and walking through solving a performance problem. Explaining concepts along the way.

Please note:

  • This is a simple example to explain how queuing works in ESXi
  • Mileage will vary depending on your workload and configuration
  • This workload is targeted specifically to make relationships easier to understand
  • PLEASE do not make changes in your environment at least until you read my conclusion at the end. And frankly not without direct guidance from VMware support.

I am sorry, this is a long one. But hopefully informative!
Continue reading Understanding VMware ESXi Queuing and the FlashArray

Issue with Manual VMFS-6 UNMAP and Block Count

So vSphere 6.5 introduced VMFS-6 which came with the highly-desired automatic UNMAP. Yay! But some users still might need to run manual UNMAP on it for some reason. Immediate reasons that come to mind are:

  • They disabled automatic UNMAP on the VMFS for some reason
  • They need to get space back quickly and don’t have time to wait

When you run manual UNMAP one of the options you can specify is the block count. The UNMAP process since 5.5 iterates through the VMFS, by issuing reclaim to a small part of the VMFS, one at a time, until UNMAP has been issued to all of the free space. The block count dictates how big that segment is. By default ESXi will use 200 blocks (which is 200 MB). Continue reading Issue with Manual VMFS-6 UNMAP and Block Count

What’s New in vSphere 6.5 Storage vSpeaking Podcast

Quick post. Recently I had the pleasure of, alongside Cormac Hogan being invited on to the Virtually Speaking Podcast hosted by Pete Flecha (Technical Marketing for VMware’s Storage and Availability products with a focus on VVols) and John Nicholson (Technical Marketing for VMware’s Storage and Availability products with a focus on vSAN) .

Had a lot of fun, we spoke of the new features of vSphere 6.5 from a core storage standpoint–a lot about what I have been posting about in recent days: UNMAP, VMFS-6 etc. This invitation was due to our work writing the “What’s New in Core Storage in vSphere 6.5” white paper.

Announcing vSphere 6.5 Core Storage white paper

Check out the podcast here:

What’s new in ESXi 6.5 Storage Part IV: In-Guest UNMAP CBT Support

This is the fourth in my series of what’s new in ESXi 6.5 storage. Here are the previous posts:

What’s new in ESXi 6.5 Storage Part I: UNMAP

What’s new in ESXi 6.5 Storage Part II: Resignaturing

What’s new in ESXi 6.5 Storage Part III: Thin hot extend

Here is another post for vSphere 6.5 UNMAP! So many improvements and this is a big one for many users. Certainly makes me happy. Previously, in vSphere 6.0.x, when in-guest space reclamation was introduced, the enabling of change block tracking for a given virtual disk blocked the guest OS from being able to issue UNMAP to that disk and therefore prevented it from leveraging the goodness it provides. Rumor has it that this undesirable behavior continued in vSphere 6.5…

leecorso

Continue reading What’s new in ESXi 6.5 Storage Part IV: In-Guest UNMAP CBT Support

What’s new in ESXi 6.5 Storage Part III: Thin hot extend

Let me start this post off with saying that the “What’s new in vSphere 6.5 Storage” white paper has been officially published and can be read here:

https://storagehub.vmware.com/#!/vsphere-core-storage/

I had the distinct pleasure of helping Cormac and Paudie with this paper. Thanks to both of them for including me and providing me with access to the engineers who wrote these features/enhancements!

So anyways, read that document for a high level of all of the new features and enhancements. Previously, I have written two posts in this series:

What’s new in ESXi 6.5 Storage Part I: UNMAP

What’s new in ESXi 6.5 Storage Part II: Resignaturing

This is a short post, mainly wanted to share the white paper, but it is important to note that VMware is still marching forward with improving VMFS and virtual disk flexibility. So I wanted to highlight a new enhancement. Thin virtual disk hot extension.

Prior to vSphere 6.5, thin virtual disks could be hot extended, but there were limits. The main one being if the extend operation brought the VMDK size to larger than 2 TB (or the VMDK was already 2 TB) the operation was not permitted:

hotextend60u2If the VM is turned on and I try to apply this configuration change, I get an error:
hotextendfail

So this is fixed in vSphere 6.5! And the nice thing is that it does not require either VMFS 6 or the latest version of virtual machine hardware. Just hosting the VM on a 6.5 host will provide this functionality:

hotextend65good

hotextendsuccess

Sweet! But this really just re-enforces my thought that there are few remaining reasons to not use thin virtual disks with the latest releases of vSphere. So much more flexible and a lot of engineering is going into them to make them better. Not much work is being done on thick-type virtual disks. Look for an upcoming blog on some performance enhancements as well.

 

 

What’s new in ESXi 6.5 Storage Part II: Resignaturing

My second post in my vSphere 6.5 series, the first being:

What’s new in ESXi 6.5 Storage Part I: UNMAP

One of the new features from a core storage perspective is a new version of VMFS. In vSphere 6.5, VMware has released VMFS 6, the first major update of VMFS in year (VMFS 5 in 2011). Not earth shattering changes, a lot of pain points have been removed and there has been A LOT of work put into VMFS 6 to improve concurrency of operations and speed up certain procedures. The first thing I want to mention is unresolved volume handling. Continue reading What’s new in ESXi 6.5 Storage Part II: Resignaturing

What’s new in ESXi 6.5 Storage Part I: UNMAP

So as you might be aware, vSphere 6.5 just went GA.

There is quite a bit of new stuff in this release and there have certainly been quite a few blogs concerning the flagship features. I want to take some time to dive into some new core storage features that might be somewhat less heralded. Let’s start with my favorite topic. UNMAP. Continue reading What’s new in ESXi 6.5 Storage Part I: UNMAP

VMFS UNMAP switches block count

A recent question I got about my UNMAP PowerCLI script was it says it was using a certain block count but when I looked at the log it was using 200. Why?

Well I blogged before about why a given UNMAP process might revert to the default block count of 200 here. Essentially, if you indicate a block count larger than 1% of the free space of the VMFS ESXi will revert it to 200. Or if the VMFS is more than 75% full it will always override the block count back down to 200. Continue reading VMFS UNMAP switches block count

Increasing VMFS capacity with vRealize Orchestrator

I am working on adding some functionality to the FlashArray workflow package for vRealize Orchestrator and one of those features is automating the process to increase the capacity of a VMFS volume. The FlashArray potion of that is pretty straight forward but what of the VMFS portion? Not much on the internet directly about this. Luckily using the vCenter SDK with vRO, this is pretty easy. Continue reading Increasing VMFS capacity with vRealize Orchestrator

FlashArray Host Group Creation PowerShell Script for VMware Clusters

New script to automatically create hosts groups on FlashArrays based on VMware ESXi clusters. This is a script I’ve had out for awhile but only recently revisited and realized it was way out of date and frankly, not very good. So I trashed most of it and re-wrote it. You can find it here:

https://github.com/codyhosterman/powercli/blob/master/createhostgroups.ps1

It is pretty self-explanatory I suppose, but it’s good to review the finer points before you run it. Continue reading FlashArray Host Group Creation PowerShell Script for VMware Clusters