Can the capacity tier of VSAN have mix of SSD and magnetic?

[MikeOD]

We currently have a small all flash VSAN.  It has four nodes, each with a 400GB SSD in the cache tier, and two 1.75 TB SAS SSD drives in the capacity tier.  We're using VSAN standard, so no erasure coding, dedupe, or any other of the "all flash" features..  Can I expand the capacity tier with one or more magnetic HDD SAS drives in each server (and is it supported?)

Mike OD

[TheBobkin]

Hello Mike,

While it would be technically feasible, it is really not a good idea and is unsupported - it would also likely tank the clusters performance:

"Can I mix all-flash disk groups and hybrid disk

groups in the same host or cluster?

Mixing disk group types (all-flash and hybrid) is not supported. This complicates operational aspects

such as balancing workloads, synchronizing components, and capacity management. All hosts in the

cluster must be configured with the same type of disk groups (hybrid or all-flash)."

https://storagehub.vmware.com/export_to_pdf/vsan-frequently-asked-questions-faq

Bob

[IRIX201110141]

No.

If you have an AFA setup than your Cache device will be only used for "buffering" the writes.

If you have an Hybrid setup than your Cache device will be used for "chaching" the read and writes.

So the capacity drives have to be HDD or SSDs but not in a mixed.

Regards,

Joerg