Let me make sure I understand the inputs first:
* Opening sizer (create project, or not)
* No changes to cluster settings.
* Hybrid, rest of page at defaults
* Workload - single, general purpose, 100 VMs, 100GB per VM.
I'm seeing 11TB usable capacity, 28.34 Raw, but only 6 servers with 100 VMs. So there must be other inputs pushing you up to 9 nodes that I'm missing.
HY-4 profile
Anyway, for the hybrid it's saying 'Raw cache per node' of 183GB.
Since it's 3 disk groups, that means 3 cache disks of ~61GB. Can't buy disks that small, but that doesn't really matter for this.
Rerunning, same inputs as above but all-flash:
* All-flash, rest of page at defaults
* Workload - single, general purpose, 100 VMs, 100GB per VM, RAID-1, Dedup: 1
Same 11TB usable capacity, same 28.34 TB raw. 6 servers. All good so far.
AF-4 profile.
Raw cache per node: 900GB. 3 disk groups = 300GB per cache disk.
Still seems reasonable.
If I understand the question though, why is all-flash asking for a total of 900GB of cache per host vs. hybrid asking for 183GB?
The sizer uses the profiles to determine minimum disk sizes: vSAN Hardware Quick Reference Guide
I've just checked the underlying calculations the sizer is using and it looks like it should be recommending a single 200GB cache disk for the AF-4 profile, but for some reason someone decided to hard-code a minimum of 300GB. Probably because it's going to be impossible to buy smaller disks so it's being 'helpful' vs. being 'accurate'. It should also be recommending that same 200GB cache disk for the HY-4 profile but is reporting the actual cache required.
I'll go ask the eng team to make the hybrid and all-flash calculations consistent. Either they should both be hard-coding minimum drive sizes, or neither should ;-)
If you have different inputs that show different results, please let me know and I'll go validate.