I’m looking to spec out a new NAS. I have a relatively small media collection, that I hope to grow as I digitize more family VHS tapes etc. Right now I have around 4 TB of data, shared across an external drive and my internal ssd.
Whats the best path forward on drives in this new NAS? I’ve heard advice for buying one big 20TB drive over multiple smaller drives. What’s best for mitigation of drive failure? Is that even a concern? If I do multiple drives, should I use RAID?
I’m a little new to this. If you have resources for learning some best practices I’m all ears.
Couple things to warn you about as I understand them (take with a grain of salt, this is what I remember from reading about this stuff quite some time ago in school).
RAID is great, but if you are performing mirroring (RAID 1) in your RAID levels, it can be dangerous to do it on multiple SSD’s of the same size. This is because SSD’s longevity is based on how many writes they have in their life time - it is a set amount. This is also why larger SSD’s will typically last longer than smaller SSD’s.
The problem therein is that if you are mirroring data between 2 SSD’s that are of the same size, when one hits that lifetime write limit, it is likely the other will do the same in very quick succession, or at the same time, meaning that mirroring was not the best idea because both disks can fail at the same time. This is not true for something like a RAID 5, and should only be something to be concerned about if, again, you are using a RAID 1, 51, or something like that etc.
If for some reason you do want to do mirroring, then look at using spinning disks instead as their mean time between failure is wider in these cases, meaning you are less likely to lose 2 disks at the same time when mirroring.
Spinning disks are also a good bet if you don’t really need the speed of the SSD’s. They are cheaper for more storage and these days you can typically find some surplus seller who can sell you a lot of them for cheaper than what you would pay new or used for new spinning disks or used SSD’s, but you will lose a lot of read/write speed. Again, which one to go with depends on what kind of data you store and how you access it.
Also make sure you understand the difference between software RAID and hardware RAID, and the benefits and downsides of using each. Hardware RAID has to be supported by your hardware, but it is much faster when it is writing any additional data to other disks (like when it clones bits onto a second drive in a RAID 1 mirror, or when it writes parity to the disks in a RAID 5). Software RAID you can set up on anything even if the hardware does not support it, so it allows more chances to play around with what you want to invest in for hardware (you can use an old PC tower as a RAID NAS even if it doesn’t support hardware RAID in it’s BIOS for example, which means you don’t have to pay a lot for an actual NAS).
As others have said as well, you also want to buy more disks than you actually need (I like to have at least 2 unused disks on hand) for cases where you get a disk failure in your RAID array. Furthermore, like others have said, this does not protect against floods, fires, a meteor falling on your house etc - and so it is good to look into a way to make off-site backups on a rotating schedule.
For this, look up what a 3-2-1 backup is and how that works if you really want to make sure your data is safe.