One last technical constraint to decide upon. Do I want to have a RAID NAS, or JBOD NAS? What does a bug spray have to do with Network Attached Storage? Read on as I try to make this one technical issue simple.
Untangling the Acronyms
Now, about the apparent reference to a brand of insect killer: it is really the acronym for Redundant Array of Independent Disks. That is, a series of separate disks being managed to work together in some fashion that makes at least one disk appear to be “redundant”. In contrast, JBOD stands for Just a Bunch of Disks. In this case, multiple disks in the NAS are seen as completely independent, separate disks, addressed separately and written to separately. If they happen to contain the same data, it is because some user copied the data to the separate disks. RAID, in contrast is actually managing the disks together as though the multiple disks are just one disk.
Different RAID management disciplines exist, but I’m really only interested in the most basic discipline, called RAID 1. In this case, the disks are “mirrored”: whatever is written on the first disk is also written on the second disk. The disks are identical in content, so that if one crashes, the second one still has all your data. This means that I have to buy twice the disk space I think I need, so that one disk can just be a copy. There are more complicated management disciplines, but they require at least 3 separate disks, or three times the disk space that is actually needed.
Who Needs This Much Protection?
Does the average home computer system need this? It depends… If you are following the 3, 2, 1 backup discipline, and if you can afford to wait for the restore process when something goes wrong, no, you don’t need this extra backup. It is something that is very handy for large storage services, such as Google, or DropBox or even Netflix. If a drive crashes while you are reading your email or watching a movie, do you want to wait for Google or Netflix to go through a restore process? Not hardly. But if the information is completely mirrored on another, still functioning disk, will you, the end user, even notice the crash? Highly unlikely.
So using a RAID discipline to manage home storage is a nice but not necessary feature. However, before you decide to forego the expense of a RAID capable device, pay close attention to the “if” in the above paragraph. You need to have a well disciplined 3, 2, 1 backup system in place. If you are like me, consistent discipline is difficult to maintain. An extra margin of safety that is automatic might be a good idea.
You should also think about how comfortable you are with keeping your data in a cloud service. I think encrypted data in a cloud service if probably safe, but it might still make you nervous to have your data in such a “public” location. If so, give a listen to HandyDad’s argument for a home RAID. I think his use case matches that of a few people I know.
In any case, I’ve decided I want a RAID 1 capable NAS. It is only a little more expensive, and it is somewhat more reliable. It is important to realize that the hard drives WILL fail. They are mechanical, and they age, just like the rest of us. If you’ve never had a drive fail, you should buy a lottery ticket.
Hopefully, this is the last technical issue I need to get into before making my decision. If any of the above was unclear, just leave a question in the comments and I’ll try to answer it in non-technical English.
Next up: using my constraints and preferences to make a choice.