[PVE-User] ZFZ questions - performance and caching

[Gregor Burck]

Hi,

here: https://pbs.proxmox.com/docs/sysadmin.html#zfs-administration

I read something about the log device:
The maximum size of a log device should be about half the size of  
physical memory, so this is usually quite small. The rest of the SSD  
can be used as cache.

So the main question is, how many RAM I should plan,...

When I should plan 5GB RAM (without desuplication) for every TB HDD I  
think I need :

minimum:

4 (hdds) x 6 (TB) x 5 (RAM) x 2 (PBS and PVE) = 120GB RAM

maximum:

6 (hdds) x 8 (TB) x 5 (RAM) x 2 (PBS and PVE) = 240GB RAM

only for the System without RAM for the VMs? That's quite a lot,....
Maybee it is better to forget ZFS and use a hardware raid controler?

The planed controler is an HP P840, wich could RAID or HBA.

Bye

Gregor