Best Raid setup on NAS

ScumLord

I just got a Synology DS1515+ NAS server with 5 3TB WD red Hard drives.

I'm looking for advice for the best way to set up raid. I want redundancy/parity to protect important files like databases but I don't know if I should spread it across the 5 drives?

I don't actually have a lot of data that's crucial. One 3TB hard drive would more than cover my needs, but it's crucial data and I want to be able to be able to replace a drive easily (which is a feature of the unit with the right setup). Speed would be important too, it will be serving a database so the faster the better.

It comes with it's own version of raid which I will use and I'm just wondering how to use the HD space. Should I stick all five drive on the one raid partition or would that be over kill? Set up 3 drives for that high speed raid with parity and put a separate raid on the other two drives.

ED E

You're a long term poster so I'm probably pointing out the obvious but it needs to be said anyways:

RAID isnt backup. RAID isnt backup. RAID isnt backup. If the disk controller in the Syn goes haywire you can still lose the lot in one go. Bad PSU, fire, spilled coffee. You get the idea.


Now that thats out of the way, I was in a similar position. Data set A: Personal, vital, irreplaceable files; Data set B: Larger, less critical but a pain to replace. I considered a Pool A highly redundant and pool B just JBOD(No RAID, just add the disks together) but in the end that makes things awkward when coming to expansion if one set needs a little more space but you end up having to give it a full bay or w/e. So now its all on a single RAID-ish setup using Flexraid(But I don't recommend that anymore). My backup service makes copies of set A in Minneapolis and set B is redundant but not backed up, an efficient use of resources.

RAID 5 is out, dont touch it. For the same reason SHR(1) is vulnerable. That leaves only one real setup I'd use:




RAID6 is nice but you may as well used SHR2 which is proprietary but allows easy expansion (you can just throw in a 5TB disk next year if you need it). Its protected by two drives worth of space so even if a drive files, and then your URE on a parity drive while recovering it can still pass and rebuild. Top notch.

ScumLord

Would I use all 5 HDs in the SHR2 arrangement. One video I watched of a guy setting up this particular NAS set 4 drives in the array and one as a hot swap (It will automatically replace a failed drive) but that seems a bit pointless.

If I set all 5 drives in the same array will I effectively have 3tb of space? I couldn't quite make that out. It looks like I might have more maybe 12tb with one drive doing parity?

ScumLord

I've educated myself a bit more and was having problems finding SHR2. But I think I've got it now. SHR2 is bassically SHR with two disks as fault tolerance instead of one? Which is bassically the same as raid 6?

ED E

Yeah, they're nigh on idential, but from my reading (don't own a Synology unit, self built instead) you get more expansion/contraction control with SHR2.

A few years ago SHR1/RAID5 would be fine, but the higher the data density (3TB at 3.5" is 6x more dense than 500GB at 3.5") goes up, URE's go up, which will prevent a RAID 5 rebuild. So you need to double up on parity drives to make sure that doesn't hurt you bad.

I'd make one pool, then you dont have to worry about allocating the right amount of space to each dataset, just add drives when you get to 90% full.