Ask your IT administrator what medium they back up all your data to and the answer is likely some form of magnetic tape storage. For many people that’d be somewhat surprising as the last time they saw a tape was probably a couple decades ago and it wasn’t used to store much more than a blurry movie or maybe a couple songs. However in the world of IT archiving and backup there’s really no other medium that can beat tapes for capacity, durability or cost. Many have tried to unseat tapes from their storage crown but they’re simply too good at what they do and Facebook’s latest experiment, using Blu Ray disc caddies as an archiving solution, isn’t likely to take over from them anytime soon.
The idea Facebook has come with is, to their credit, pretty novel. Essentially they’ve created these small Blu Ray caddies each of which contains 12 discs. These are all housed in a robotic enclosure which is about the size of a standard server rack. Each of these racks is capable of storing up to 10,000 discs which apparently gives rise to a total 1PB worth of storage in a single rack. Primarily it seems to be a response to their current HDD based backup solutions which, whilst providing better turn around for access, are typically far more costly than other archiving solutions. What interests me though is why Facebook would be pursuing something like this when there are other archiving systems already available, ones with much better ROI for the investment.
The storage figures quoted peg the individual disc sizes at 100GB something which is covered off under the BD-R XL specification. These discs aren’t exactly cheap and whilst I’m sure you could get a decent discount when buying 10,000 the street price for them is currently on the order of $60. If they’re able to even get a 50% discount on these discs that means that you’re still on the hook for about $300K just for the media. If you wanted to get a similar amount of storage on tapes (say using the 1.5TB HP LTO-5 which can be had for $40) you’re only paying about $27K a tenth of the cost. You could even halve that again if you were able to use compression on the tapes although honestly you don’t really need to at that price point.
Indeed pretty much every single advantage that Facebook is purporting this Blu Ray storage system to have is the same benefit you get with a tape drive. Tapes are low power, as their storage requires no active current draw, are readily portable (and indeed there are entire companies already dedicated to doing this for you) and have many of the same durability qualities that DVDs do. When you combine this with the fact that they’re an already proven technology with dozens of competitive offers on the table it really does make you wonder why Facebook is investigating this idea at all.
I’d hazard a guess it’s just another cool engineering product, something that they’ll trial for a little while before mothballing completely once they look at the costs of actually bringing something like that into production. I mean I like the idea, it’s always good to see companies challenging the status quo, however sometimes the best solutions are the ones that have stood the test of time. Tapes, whether you love them or hate them, by far outclass this system in almost all ways possible and that won’t change until you can get Blu Ray discs at the same dollars per gigabyte that you can get tapes. Even then Facebook is going to have to try hard to find some advantage that Blu Rays have that tapes don’t as right now I don’t think anyone can come up with one.