ideal drive capacity and RAID type

[Big Jim]

My Home NAS, which is used for:
general storage of personal files.
storage of all media for home cinema viewing
backup of business server .

Current setup is
Server chassis with super micro motherboard,
xeon cpu
16GB ECC Ram
Running XigmaNAS (an older build still branded NAS4Free), will upgrade this to latest version when I do this upgrade.
5 x 4TB WD Red (CMR version) in RAID z-2, this gives me a little over 10TB usable, usage now around 8/9TB.

I bought 4 more 4TB WD Red drives to go in it about 18 months ago and never got around to installing them simply because they weren't needed.

am now wondering which way to proceed.
obviously the intention was to backup all of the current data (which has been done) then build a new RAID array using all 9 drives.
Should I go RAID z-3, should I sell all of the drives and upgrade to bigger capacity ones ?
Current drives have been in place for a few years so will likely have over 20k hours on them. I expect I might get £40 per drive and perhaps £70 each for the sealed ones, which is roughly £500, not enough money to directly replace these for exact same capacity, although a couple of 18TB drives in RAID 1 would set me back £600 and should in theory be more reliable ?
but I'm losing a chunk of capacity if I do that.

Any thoughts ?

 

[Blues]

I would go with the 9 drive setup you initially planned unless the migration of data off and back will be too big of an issue.

 

[NviGate Systems]

Whenever I setup a RAID, I always tried to make one I could in a pinch disconnect the drive to get data manually to save my butt. (This was for customer backups back when the best drive I could squirrel away were 1TB)

When I think about 18GB x2 in Raid 1, it's a bit too...um...risky. I'd rather do something like raid 10 so at least I can suffer more disk losses. A 8 disk RAID array can suffer 4 disk losses just not on the same slice/etc.

I avoid Raid that uses parity as although rare, the raid controller can write corrupted parity and there is no recovery from that unless you have backups.

Of course, I haven't used Raid in ages so there may be new fangled types, but the more complex it is, so the recovery is too. Plus, not every device uses the same parameters for RAID, and recovering from NAS arrays are among the most expensive recoveries aside from drives that need surgery.

 

[nlinecomputers]

Why Raid z3? I would think that z2 would be a better fit for 9 drives.

 

[YeOldeStonecat]

How many drive bays/connections can the host take?
Of ZFS Raid, z2 is a good mix, you get 2x drives for parity...versus 1 of z, and you don't really need 3x parity drives of z3 ....you lose too much capacity.

 

[Big Jim]

How many drive bays/connections can the host take?
Of ZFS Raid, z2 is a good mix, you get 2x drives for parity...versus 1 of z, and you don't really need 3x parity drives of z3 ....you lose too much capacity.

I was only thinking of Z3 in terms of rebuild times becoming an issue with more drives in the array.
The host machine can fit probably 12 drives in it (not 100% sure as I haven't opened it up in a while)
I have had a HP microserver Gen 8 donated to me though which I could use instead if I went down the route of using less (but larger capacity) drives. it would be easier to find a place for that in the house than the current 4u server chassis.


It has taken me over 10 years to accumulate this much data, however with the bulk of it being 4k movies to stream over the home network I imagine it will fill up faster in future as Blu-rays/4k blu rays take up much more space than DVDs.