Flash cache ssd no longer in compatibility guide

I have 6 vsan disk groups; each group consists of an ssd for cache and 7 hdds for capacity. Suddenly, the flash cache ssds in each host is not supported in the vsan compatibility guide any more...for the version of esxi / vsan that's currently running on those ssds. Thanks again, vmware. 😞 


My actual question: For clarification, if I replace the ssd cache drive in a vsan disk group, it wipes and rebuilds the disk group it's attached to, correct? If yes, is this a long process? 4TB SSD, 7 6TB HDDs in each disk group.


Backstory / PSA for anybody else who's "remediate" button is greyed out:

Several months ago I upgraded my VCSA and then 2 clusters of 6 hosts to esxi 7.0GA. 

Over the last few months I've slowly upgraded as new versions come out.

As of today, these 12 hosts are on v7.0u2a, and have been for about 2 months-ish. 

A couple days ago, after fighting with veeam CDP io filters for an eternity, I finally got those io filters uninstalled (manually), and now it's time to install them.

(Hang on, this really IS about vsan! Soon!)

In order to finish the io filters install, it's necessary to remediate the hosts.

That went well with my production cluster, so I moved to my DR cluster, but...



After a bit of research, I determined that the reason is that the flash cache ssd in each host is not supported in the vsan compatibility guide.

For the esxi version that's currently running!

What? I upgraded to this esxi version using an image-based upgrade path a few months ago, with no issues!

So, vmware has changed their mind, apparently. Great. Just like back in the early days of 6.0 when vmware suddenly decided that they don't support SATA drives for vsan, and we all had to go replace our entire stack of SATA HDDs and buy new SAS HDDs.



0 Kudos
2 Replies

  1. Somewhat similar situation here. the non-volatile memory controller of the Micron 9700 Pro flash drives in everyone of my 10 nodes has dropped off the list. All the other health checks on the drives pass. What to do? I can't replace 100 drives, and we need to upgrade to VCF 4.3.1 to close the vCenter vulnerabilities. WTF!
0 Kudos

The answer to your question is yes, to replace the cache disk, you have to recreate the disk group. 

0 Kudos