I am looking at buying a cost-effective machine for using openAttic, which is simply Ubuntu 14.04 64bit with ZFS.
The server I am looking at gives me 8 bays of 3.5", where I plan to put SAS 7.2k enterprise grade HDDs, probably 3Tb or 4Tb. I'm aiming for 18Tb to 24Tb of usable space, with 2 HDDs for redundancy. I'll get 32Gb of ECC RAM at least, but I will look at cost of 64Gb.
I am not experienced enough with ZFS, but initially my plan was to use a small boot and system partition, mirrored across all the drives, using ext4. Then using the remaining space for ZFS.
The server has an M.2 slot: Should I get an M.2 SSD there to use as the boot/system drive? OpenATTIC needs very little for the system partition, so it seems like a waste to get a premium SSD for that, when RAM and the SAS drives will be doing most of the work and will be the bottleneck.
I have read that ZFS likes to get direct access to the disks, so I wonder: Can ZFS can work well when you configure it to not use the whole disk? Or should I get the SSD and let ZFS take all the SAS disks?
If money is not a limitation, of course I get the SSD, but I am looking for "best value for money". Thanks!