Yellow Bricks

by Duncan Epping

vSAN Storage Rules policy capability allows to set dedupe/compression/encryption per VM? The 2026 update!

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It seems to be a regularly question, and with most recent releases things have changed once again, so I figured I would rewrite my post and point from the original to this update. So what is the question? When you create an SPBM policy you will see a screen which seem to indicate that certain data services can be enabled on a per VM basis. Those data services would be Encryption, Compression, Deduplication, and Hybrid or All-Flash. This is not the case of course, the Storage Rules section was intended to specify which storage services needed to be enabled (or disabled) for a particular datastore to show up as compatible with the policy.

Now with 9.1 various things have changed, and I want to call this out. First of all, when you have Auto-RAID enabled for the policy you don’t even see all the options any longer.

Now, when you disable Auto-RAID the below is what it looks like.

Confusingly, this seems to indicate that these options were only here for disabling/enabling dataservices, however we now that this is not the case. So let’s clarify what these do and which version does what, as I am mildly confused as well at this point. I created a table which hopefully helps explaining how this works and what does what?!

VersionServiceRuleFunction
All versions
(OSA and ESA)		EncryptionData-At-RestWill only present datastores which have data-at-rest-encryption enabled
All versions
(OSA and ESA)		EncryptionNo encryptionWill only present datastores which have data-at-rest-encryption disabled
All versions
(OSA and ESA)		EncryptionNo preferenceWill present datastores with or without data-at-rest encryption enabled
All versions
(OSA)		Storage tierAll flashWill only present datastores which are All-Flash
All versions
(OSA)		Storage tierHybridWill only present datastores which are Hybrid
All versions
(OSA)		Storage tierNo preferenceWill present datastores that are All-Flash or Hybrid
All versions
(OSA and ESA)		Data ReductionDeduplication and compressionWill only present datastores which have deduplication and compression enabled
All versions
(OSA and ESA)		Data ReductionCompression onlyWill only present datastores which have compression enabled
vSAN 9.1 and later
(ESA)		Data ReductionNo data reductionWill only present datastores which have compression disabled, it will not disable compression or deduplication!
Pre vSAN 9.1
(ESA)		Data ReductionNo data reductionDisables Compression on all objects associated with the policy
All versions
(OSA)		Data ReductionNo data reductionWill only present datastores which have compression disabled, it will not disable compression or deduplication!
All versions
(OSA and ESA)		Data ReductionAll versions (OSA and ESA)Will present datastores with or without deduplication and compression enabled

HDD attached to MacOS constantly rattling/spinning?

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I have an HDD attached to my Mac for backups and as storage for photos which are archived. (I don’t think this is MacOS version specific, but for me this happened with MacOS Tahoe 26.7. The last couple of days I noticed that my disk was constantly rattling / spinning, to the point where it started to annoy me. I rebooted my Mac, but it made no difference. I looked at the Activity Monitor and couldn’t identify what was causing this, so I opened up the terminal and managed to figure it out pretty quickly using the following command:

sudo lsof +D /Volumes/Backup

This provided a list of all the different processes, and users, accessing that particular volume. I noticed that command “mds_store” with user “_mds_stores” was accessing the disk constantly in various directories. A quick search revealed that this is MacOS Spotlight indexing and cataloging files to speed up search. As the disk is just used as a backup target I decided to disable the indexing of the volume the following way:

  • Open System Settings
  • Go to Spotlight
  • Scroll down to “Search Privacy…”
  • Click “+” to add the volume you want to exclude from being indexed and click Done

Within seconds, literally, the rattling stopped and I regained my sanity.

Will vSAN OSA Hybrid be available in future versions?

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I’ve had this question three times in the past two weeks surprisingly enough, will vSAN OSA Hybrid be available in future versions? I thought most people would have known or heard by now, but apparently that is not the case. With the release of VCF 9.0, and vSAN 9.0, a deprecation notice was releaaed for vSAN OSA Hybrid. The same applies to RDMA for vSAN OSA. It was listed in the release notes here.

Deprecation of the hybrid configuration in vSAN Original Storage Architecture (OSA):
The hybrid configuration in vSAN Original Storage Architecture feature will be discontinued in a future VCF release.

Deprecation of support for vSAN over RDMA:
The support for vSAN over RDMA for vSAN OSA will be discontinued in a future VCF release.

Note, this means that vSAN OSA All-Flash has not been announced for deprecation, just the hybrid variant. Also note, that for hybrid the release at which it will be deprecated has not been officially announced either, but expect it to be in a major upcoming version.

#127 – Drew Nielsen introducing the overhauled VCDX program!

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I bumped into Drew Nielsen at Explore in Las Vegas and we briefly discussed the overhauled VCDX Program. Not only did the name change from VMware Certified Design Expert to ⁠VMware Certified Distinguished Expert⁠, the whole program has been overhauled with job specific tracks for the various personas. Where the focus was on architects in the past, Broadcom now made the top tier certificationt track accessible for support engineers, administrators, and of course still for architects. Besides sharing the details of the renewed VCDX program, Drew also discusses what has changed for the VCAP exams. If you are interested in getting certified, this is a must listen! Oh, and before I forget, the price of the VCDX exam has been lowered to 250 USD from 995 (and 3000 USD before that).

You can listen to this episode via Spotify, Apple, or anywhere else you get your podcasts. Make sure to leave a review or a rating, as that is how other people find the podcast. You can also watch the video on youtube, or use the embedded players below!

Host placement for the secondary FT VM with Fault Domains?

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On Reddit there was a question about how to specify on which group of hosts the secondary VM of an FT-enabled VM would land on. Now this is a problem that has been around for a while, and for the longest time we actually did not have a solution for it, but now we do. I did a quick search, and somehow I couldn’t find an article where I describe how this works, so I figured I would write one. Having said that, I would not be surprised if there’s already and article out there, but somehow didn’t pop up.

When it comes to vSphere Fault Tolerance, when you enable it on a VM, what you will see happening is that the VM you enabled it on will get “(primary)” behind the name. This VM is, as you would expect, the primary and is paired with a “secondary”. This “secondary” VM runs in lockstep with the primary, so that it can take over instantly if the primary would fail for any reason. Now, that secondary VM is kind of a strange VM. Although you can find the VM in your inventory on a host level, you cannot find it on a cluster level or in the VM view. It is like a shadow copy, it is there, but yet it isn’t really.

As a result, making VM-Host rules for it is rather difficult. Although you can do it, this shadow / secondary VM can also be reinstantiated and as a result that VM-Host rule would unfortunately break. Why? Well, the newly instantiated VM is literally that… a newly instantiated VM, so the old rules do not apply. So although the VM-Host rules with tags can work through the Compute Policy option, it not ideal. Probably should also mention, traditional VM-Host groups and rules do not even work with the secondary VM, as you simply cannot select the secondary VM to begin with.

So what does work? Well, there’s a new option called Enable Metro Cluster Fault Tolerance. What this does is that when you select a Host Group for the primary, the secondary VM automatically ends up on a host outside of the selected group. The Host Group can simply be defined via the VM-Host group option under your cluster’s Configure tab as shown in the screenshots below.

Hopefully this helps those who are planning on leveraging FT and want to ensure the primary and secondary are placed on different fault domains.

Host placement for the secondary FT VM with Fault Domains?