Doing a build out for a VDI cluster and we are getting quotes for an AF-vSAN. The vSAN will be running in RAID 6 with compression, dedup, and encryption enabled with a workload of Windows 10 full-clones and persistent data.
The vendor is doing a mix with the following:
Cache: 800GB SSD SAS 12Gb x 2 (4k reads @ 240k, 4k writes at 130k)
Capacity: 1.92TB SSD SATA 6Gb x 6 (4KB reads @ 90k, 4KB writes @ 50k)
Each node will have two disk groups comprised of a 800GB cache drive with 3x1.92TB drives for capacity.
I have some room in the budget to jump up to 1.6TB SAS drives for the capacity tier. This increases cost per drive and I lose 1.8TB of space per a node. The gain is a capacity tier where each drive has 4KB reads @ 200k and 4KB writes @ 90k.
Does anyone here have experience with using a mixed SAS cache and SATA capacity tier for an AF-vSAN deployment? For VDIs, would you save money and use a mix of SAS and SATA or SAS across both tiers?