I'm looking into building a NAS for file storage, and I'm trying to determine the right scenario for my use case. I'm looking for about 32TB of raw storage, and no less than 16 useable given a redundant RAID array. I'll mostly be accessing files that are at least 500MB, up to 75-80GB. Right now I'm seeing a 4TB*8 drive array or an 8TB*4 drive array as my best options: it's about the same cost (larger array is $20 more), storage space isn't an issue, and the drives are NAS optimised, so I'm not concerned about heat or vibrations.
My NAS will be in one place, and I'll be remotely accessing files from another location (5 users at a time, or thereabouts), with network speeds of about 100Mbits/second consistently. I'm seeing RAID 10 or RAID 6 as my safest and most viable options, alongside a 16TB offsite backup once a month in cases of corrupted data within the array. Processing power shouldn't be an issue, so I can't see calculating parity as being a major roadblock. RAID 10 would drop me to my minimum of 16TB storage, with excellent reads and writes, but I don't know if those would matter at all if my network is the theoretical bottleneck anyway. RAID 6 on the 8*4 would also bring me to 16TB. RAID 10 on the 4*8 array grants me 16TB of storage, with more theoretical throughput, as there's striping between more drives. RAID 6 on the 4*8, however, gives me 24TB of storage, 2 drive parity, ease of replacement (1 drive failure is half the cost of the other array), and an easier time rebuilding the array should a drive failure occur (less storage per drive). Am I missing something? Are there advantages to a smaller array with higher capacity drives, besides the aspect of portability and size (which shouldn't be a problem here, as the array isn't moving)? Thanks!