Many of you will be aware of the new core storage features that were introduced in vSphere 6.5. If not, you can learn about them in this recently published white paper. Without doubt, the feature that has created the most amount of interest is automated unmap (finally, I hear you say!). Now a few readers have asked about the following comment in the automated unmap section.
Automatic UNMAP is not supported on arrays with UNMAP granularity
greater than 1MB. Auto UNMAP feature support is footnoted in the
VMware Hardware Compatibility Guide (HCL).
So where do you find this info in the HCL? I’ll show you here.
A short post to let you know about some upcoming speaking engagements that I am doing over the next couple of weeks.
First up, I will be speaking at the TechUG, or Technology User Group event next week. This event will be held on Thursday, November 26th. It will be held in the Westin Hotel in the heart of Dublin city, Ireland. There is a really good agenda for this event (which is not a VMware centric event), that you can find at this link here. I personally will be speaking about Virtual SAN (VSAN), VMware’s hyper-converged compute and storage platform. This will be more of an introductory type session, but I’ll also be giving an overview of new and upcoming features and where we are thinking about going next with VSAN. You can find the Dublin TechUG registration link here.
My next session is at the VMUGDK Usercon or Nordics Usercon, which will be held on Tuesday, December 1st. This event will take place at the Scandic Hotel in Copenhagen, Denmark. This year I will return to my roots and talk about core vSphere storage enhancements over the past few releases, and also a look at some upcoming plans. No VSAN, VVol or anything like that – this will be a discussion on VMFS, NFS, VAAI, PSA, etc. The Nordic UserCon details can be found at this link here. The registration link is at the same location.
If you are in the Dublin or Copenhagen area for any of these events, I’d love to see you there. I plan to spend most of the day at both events, so if there are any VSAN or vSphere storage questions or feedback that you’d like to give me, I’d be delighted to talk with you in person.
A short post today, but it highlights what I feel is an important enhancement to vSphere licensing. I’ve had lots of questions recently about why VAAI (Storage APIs for Array Integration) is not available in the standard edition of vSphere. This is especially true since I began posting about Virtual Volumes earlier this year, and it was clear that Virtual Volumes is available in the standard edition. One reason why this was confusing is that if a migration of a VVol could not be handled by the array using the VASA APIs, the migration would fall back to using VAAI offload primitives. But if you only had standard licensing for VVols, would you still be supported?
A few weeks, my good pal Cody Hosterman over at Pure Storage was experimenting with VAAI and discovered that he could successfully UNMAP blocks (reclaim) directly from a Guest OS in vSphere 6.0. VAAI are the vSphere APIs for Array Integration. Cody wrote about his findings here. Effectively, if you have deleted files within a Guest OS, and your VM is thinly provisioned, you can tell the array through this VAAI primitive that you are no longer using these blocks. This allows the array to reclaim them for other uses. I know a lot of you have been waiting for this functionality for some time. However Cody had a bunch of questions and reached out to me to see if I could provide some answers. After conversing with a number of engineers and product managers here at VMware, here are some of the answers to the questions that Cody asked.
I’ve been hit up this week by a number of folks asking about “ATS Miscompare detected between test and set HB images” messages after upgrading to vSphere 5.5U2 and 6.0. The purpose of this post is to give you some background on why this might have started to happen.
In vSphere 5.5U2, we started using ATS for maintaining the heartbeat. Prior to this release, we only used ATS when the heartbeat state changed. For example, referring to the older blog, we would use ATS in the following cases:
Acquire a heartbeat
Clear a heartbeat
Replay a heartbeat
Reclaim a heartbeat
We did not use ATS for maintaining the ‘liveness’ of a heartbeat. This is the change that was introduced in 5.5U2 and which appears to have led to issues for certain storage arrays.
Recently I published an article on Virtual Volumes (VVols) where I touched on a comparison between how migrations typically worked with VAAI and how they now work with VVols. In the meantime, I managed to have some really interesting discussions with some of our VVol leads, and I thought it worth sharing here as I haven’t seen this level of detail anywhere else. This is rather a long discussion, as there are a lot of different permutations of migrations that can take place. There are also different states that the virtual machine could be in. We’re solely focused on VVols here, so although different scenarios are offered up, I highlight what scenario we are actually considering.