I need some advice on replacing my existing 16 TB array (10x2TB RAIDZ2). I don’t think I need a ton of storage so I’m looking at about 3x the storage (~50-60TB) and here is what I’m considering (serverpartdeals.com):

Size Model Type Price Price/tb No. Drives Total Price Usuable storage (RAIDZ2) Total price/tb
16TB HC530 recertified $157 $9.8/tb 5 $785 48 TB $16.3/tb
18TB X18 refurbished $161 $8.9/tb 5 $805 54 TB $14.9/tb
18TB X20 recertified $179 $9.9/tb 5 $895 54 TB $16.5/tb
14TB HC530 refurbished $128 $9.1/tb 6 $768 56 TB $13.7/tb
14TB HC530 recertified $144 $10.2/tb 6 $864 56 TB $15.4/tb
16TB HC550 recertified $157 $9.8/tb 6 $942 64 TB $14.7/tb

* 14TB HC530 only has only available in-stock.

I’d like to continue using ZFS (RAIDZ2) and if I understand correctly, expandable RAIDZ(2) is coming soon so I’m assuming I can expand in the future if needed.

Can anybody give me any advice?

I’ve never used enterprise drives before and I’ve also never purchased refurbished or recertified but it’s a lot cheaper than buying new and/or WD RED, etc.

I’m also unsure the differences between Exos and Ultrastar but I think X18 is older and so is HC530. All the drives listed have a 2-year warranty which I guess is sufficient.