I do not understand why do you need such a setup for the VM storage filer. And i do not know what a VM storage filler does ... yet :)
SAN storage for virtual machines. One of the nastiest, stressiest applications there is for ZFS. I've been talking about this for months. You mean you haven't been reading every single post I've written, and pieced it all together? Heh.
https://forums.freenas.org/index.php?threads/change-iscsi-drive-type.27121/#post-173508
Our environment here isn't that large, that stressy, or that nasty, because over the last half a decade we've carefully restructured stuff to be VM-friendly - our VM's do not assume they have resources all to themselves.
For VM storage, though, RAIDZ doesn't work well, and you need mirrors. If you use two-way mirrors, then the failure of one drive means you no longer have redundancy within that vdev. This shortcoming can be repaired by going with three-way mirrors. But drives sometimes have a manufacturing batch defect, so putting three drives from the same manufacturing run introduces a stronger possibility that all three drives could catastrophically fail in a similar manner in a short period of time, hosing you.
Therefore selecting a heterogeneous set of drives decreases the likelihood that you will experience simultaneous failures. Usually people just pick two different manufacturers. I might just end up doing this since there's no strong indication of a third manufacturer coming to the party; the WD Green 2TB 2.5 has been out for a Very Long Time and the Reds are usually very similar to the Greens (mostly just different firmware).
I could also move on up to SAS drives where there are several options, but at $400+ each, that was deemed not desirable.
But mostly it's because of the rage involved when a major failure happens, so lots of engineering goes into trying to avoid major failures.
I want to put all the 8 drives in a 2x5,25" bays, space so i do not think that my SM case can accept 15mm 2,5" HDD's and that is the reason why i needed them small 9,5mm thick.
Most Supermicro cases are designed towards enterprise 2.5" drives, which are usually 15mm.
M9T is the only one 2TB in size... btw made by Seagate it is not Samsung anymore.
Designed by Samsung engineers and originally built in a Samsung factory, bought out by Seagate. I'd say that's Seagate in name only.