SAS vs SATA question for virtualization use-case

Hi all,

I recently acquired an HP Z240 Workstation with Xeon E3-1270 v6 (4Cx3,80GHz+HT), 16GB DDR4 RAM, 512GB SATA SSD and NVS 315.

I want to use it as an all-in-one, always-on, home server for backups, NAS, Plex, NextCloud, Bitwarden, etc. I will host Ubuntu VMs and Docker containers, on top of Proxmox (running Proxmox from the 512GB SSD).

I believe I will need max 4 TB usable space. I consider purchasing 2 SATA HDDs x 4TB (7K RPM), which I will set-up as a ZFS pool with RAID 1 (mirror). Or would 4 hdds x 2 TBs perform better?

As this is a SATA-based mother-board and considering my use-case, I am not sure if it’s worth investing in a (used) SAS HBA controller and disks? In Europe these are more difficult to find and considerably more expensive than in the US!

I have been reading up people mentioning SAS is an absolute minimum for virtualization. Do you think that makes sense for my use-case?

From what I reckon based on actual performance tests, for similarly spec’d drives (e.g. in the 7K RPM range), SAS disks only very marginally outperform SATA drives. It seems you only get meaningful performance improvements from SAS drives with really higher RPMS (e.g. in the 15K range), which is to be expected…

In the NAS Killer 5.0 recommendations page, I mostly see 7K drives being recommended. Do you think is absolutely required to go with higher RPMs/SAS drives for virtualization?

Finally, introducing a SAS HBA controller like LSI will introduce a SPoF in my system, which I am not very fond of. This is not an enterprise-grade system. I don’t even think I can put 2 of these controllers. Any idea how often do these controllers fail?

I very much appreciate your ideas and guidance, in advance!