Storage Policies, SSDs ?

[comoblc]

First time with VSAN

If I have 6 hosts with a mix of SSDs and rotating drives, is it possible to force specific VMs to use the SSDs or do I need to create a separate VSAN cluster?

6 hosts:

Host 1-3 has 1 SSDs and 8 rotating each

Host 4-6 has all SSDs

Thanks

[zdickinson]

The SSDs are used as a caching layer that de-stages to the HDD.  There is no concept of putting a VM on SSD vs HDD, every write will pass through the SSD and hopefully a majority of reads will come from here as well.  Thank you, Zach.

[JohnNicholsonVM · Accepted solution]

There is a means to set a "Flash read cache reservation"  on a hybrid VSAN so a VMDK can in essence "live" in the caching tier on a hybrid configuration.

Honestly our caching isn't some simple FIFO buffer (we are working on publishing a good 8 page read on it) so unless your having problems and support is directing you to reserve cache, I'd trust ARC and the other systems we use to be smart enough to get the job done.

FYI :The default policy is mirror once, stripe none, no force provisioning, no space reservation.

You can have a lot of fun with policies, but I'm curious what is your use case?

[comoblc]

Thanks!

It was more of attempting to understand VSAN