Facebook Puts 10,000 Blu-ray Discs In Low-Power Storage System

itwbennett writes "Facebook said last year that it was exploring Blu-ray for its data-center storage needs, and on Tuesday it showed a prototype system at the Open Compute Project summit meeting in San Jose, California. It designed the system to store data that hardly ever needs to be accessed, or for so-called 'cold storage' (think duplicates of users' photos and videos that it keeps for backup). The Blu-ray system reduces costs by 50% and energy use by 80% compared with its current cold-storage system, which uses hard disk drives, said Jay Parikh, Facebook's vice president of infrastructure engineering." It's a prototype, and they're also evaluating low power flash as another alternative to keeping seldom accessed data on hard drives.

Comments

Write once?

[WPIDalamar]

Anyone know if these burners are write-once drives?

If so, it pretty much guarantees that Facebook keeps a copy of your stuff forever, even if you "delete" it.

Re:Write once?

[tripleevenfall]

Doesn't Facebook have a right to control over their product? (you) ::ducks:::

Re:Write once?

[StripedCow]

When you delete your account, somebody will go and get the corresponding disk, copy it (except your data), and destroy the old disk.

It's write-once only if you don't consider "destroy" a write-operation.

Re:Write once?

[lagomorpha2]

If so, it pretty much guarantees that Facebook keeps a copy of your stuff forever, even if you "delete" it.

Facebook keeps a copy of your stuff forever, even if you "delete it". So does gmail/google. Even stuff you type into a textbox but never submit.

http://www.slate.com/articles/...

Come to think of it, "deleted data" is probably exactly what this cold storage is for. They never have to worry about overwriting it when users change the data because it's data the users have already "deleted".

Re:Write once?

[mlts]

Some technologies come full circle. I'm reminded of Kodak's optical storage technologies that stored 3-6 gigs on large (8 inch?) MO platters in a jukebox that had its built in "clean room". The advantage of this technology was the fact that once burned, the data was there forever, which was useful for long term archiving.

Rewritable MO disks came out in drive arrays after that, arrays that had the ability to flip disks, so it could read/write the both sides (300 megs per side.)

Optical tech ended up on the sidelines because tape got cheap, especially when DLT started having decent capacities and tapes with WORM capabilities hit the data centers.

Now, tape drives are very expensive, and require a LOT of I/O on the attached computer, or else they will shoe-shine themselves into oblivion.

In the past, optical burners had issues, buffer underrun was one of those. Now, with modern ones that just turn off the laser once the buffer empties and resume very close to where it left off once data starts arriving again.

With tape out of the price range, I have not understood why someone hasn't made a Blu-Ray autochanger. Sony has one, but it is a carousel unit made for playing. However, couple that with a BDXL drive, "flippy" disks that have two sides for twice the writability, and that would provide more than adequate storage on an archival basis for large volumes of data. Two autochangers will allow one to have the ability to move data offsite, and almost every backup program out there has some form of encryption on it.

I just don't see why this isn't done. Even a 5-10 Blu-Ray autochanger that used five disk caddies (so one could just load the pack, and then not have to touch the media after that) would be immensely useful for critical backups.

Re:Write once?

[Chris Mattern]

When you delete your account, somebody will go and get the corresponding disk, copy it (except your data), and destroy the old disk.

Except they won't. Facebook doesn't delete your data when you delete you account *now*, what makes you think they'll do it when it becomes this much harder?

Re:Write once?

[Grishnakh]

Huh? How would a 5-10 Blu-Ray autochanger be userul for backups? 10 BDs equals a paltry 360GB of data storage; that's only enough for 1/3 of a typical 1TB hard drive. BDs are nearly useless because they simply don't store much data; why FB is bothering with them, I have no idea. Optical discs have always been found to be pretty awful in terms of storage capacity and data integrity over time compared to tapes. The only problem tapes have is the drives are expensive, but large companies don't have a problem with spending $2k on a drive. On a per-GB basis, they're easily the cheapest thing out there.

Re:Write once?

[Guspaz]

How do you get 36GB per bluray disc? Commercially available BD-R discs come in a variety of capacities (25, 50, 100, 128) depending on number of layers and density, and 36GB isn't one of them.

10 BDs equals up to 1280GB of storage for quad-layer high density discs, although I can't find any of the 128GB discs for sale, only 100GB discs. Either way, the higher capacity discs are rather expensive, but if you're buying them in big enough bulk, it may not matter as much.

Re:Write once?

[Solandri]

There are larger capacity BDs, but they still don't amount to much storage. As others are speculating, this is probably a pre-emptive action by Facebook, so when they eventually get sued for not deleting someone's data, they can truthfully testify in court that it's logistically "too hard" to comply with a single user's delete request.

Re:Write once?

[wiredlogic]

When I started at Kodak in 2000 they were ramping down development on their DOTS product for Digital Optical Tape Storage. It used optical film spooled in a cartridge in an automated mini-lab type machine to process data stored on the film with exposure from LEDs. Each cartridge was 1.2TB and has a 100 year shelf life. For long term, write-once archival storage it is very cost competitive against magnetic tape but they just gave up on it. The cool thing is that it looks like a company acquired the patents and is going to bring it to market after all these years.

Re:Write once?

[CTachyon]

Anyone know if these burners are write-once drives?

If so, it pretty much guarantees that Facebook keeps a copy of your stuff forever, even if you "delete" it.

Where I work, we use large-scale tape backup (complete with robots), but tapes are so crappy that you basically have to treat them as write-once media anyway, so you have the same problems. (And tape drives are a consumable, but that's another story.) We solved this by encrypting each backup batch with a unique symmetric crypto key, and when a backup expires a cron job throws away the crypto key and marks the batch as "deleted" in our tape index. If all the batches present on a given tape end up deleted, only then do we bother to recall the physical tape from off-site storage and throw it out.

Has the bonus that we don't have to trust the security of our off-site storage provider.

Tape?

[jythie]

I guess tape just isn't sexy anymore.

For cold storage it is still pretty hard to beat, but I have noticed a lot of tech companies have blinders regarding 'stodgy' technology.

Re:Finally a demonstration

[NotQuiteReal]

I predict the squirrels win. The one ox will eventually die, but a thousand squirrels is a viable population.

Lots of redundant data

[Rik Sweeney]

It designed the system to store data that hardly ever needs to be accessed

So that will be several million inactive profiles. I hope they've made their solution scalable, pretty soon they'll be storing 75% of their current profiles on those discs.

Re:Out of touch

[MightyYar]

Ah, nevermind. I saw the $20 per 100 price on Google shopping. But when I cilck on it, they are just DVD-Rs. Blu Ray seems to be $1, which puts them in a similar price/gig with hard drives. Mods, kill my original post please! :)

Longevity will be an issue

[Marxist Hacker 42]

NONE of those solutions, including the current one, have been tested for longevity.

I went a year between my honeymoon and getting pictures off of my 1st gen digital camera, stored in flash memory. About half were corrupt.

Re:Longevity will be an issue

[mlts]

I've yet to find a single media solution that has stood the test of time. Yes, I might be able to pull data from a tape from the 1990s, or a burned CD from 1998... but I wouldn't want to bet my data on it. Long term, the only way to do things is archive data in a format that detects (and corrects) errors (I use WinRAR, but .PAR archives work as well) and keep moving them forward in media.

Even cloud storage is unreliable. I have had sync errors completely flatten my TC volumes stored on DropBox, and restoring from Amazon Glacier is doable... but is something I have as an absolute last resort.

Re:Longevity will be an issue

[Anonymous Coward]

For that first year, he was probably trying fucking a bit harder rather than worrying about data recovery. Priorities, lonely internet dude, priorities.

Re:Longevity will be an issue

[GrumpySteen]

I've yet to find a single media solution that has stood the test of time.

Clay tablets. Tested and proven for 5,000+ years and counting.

Space required for storage may be an issue, though.

Tape?

[bored]

Sounds like what they really want is tape..

Besides the difficulty of dealing with 174 bluray disks instead of 1 tape... You have to wonder about the reliability of those disks sitting around on a shelf for ten years..

Oh, and you can write said tapes at 500+ MByte/sec.

Plus, tape is well understood, and there are tons of media management applications that track whats on the tape, when it expires, where its located, what encryption keys are used to decrypt it.. Basically 40 years of data management infrastructure.

I'm surprised it beats LTO-6

[hawguy]

LTO-6 holds 2.5TB/tape (native, not compressed), so it's more space dense than Blu-ray since a single tape can replace fifty 50GB bluray disks. A 1 petabyte cabinet would only need 400 tapes, and LTO tape libraries of that size are readily available off the shelf - plus the software to manage it is also off the shelf.

Cost-wise, the tapes and disks are around the same, branded dual-layer blurays seem to cost $1 - $2, and LTO-6 tapes are around $60.

The only advantage I can see for blu-rays is in random access performance, but for a rarely used cold archive system, you'd think that wouldn't matter.

Re:No tape?

[mlts]

For a drive + 50 BD-R disks per TB, I'm looking at a C-note for the drive and $25 for each terabyte after that.

For a modern tape drive, I'm looking at $3500 for the drive and $65 per 2.5 TB, native capacity.

This also doesn't include hardware and software. For the LTO-6 drive, I need a dedicated server with a SAS card and a high end backup program. For Blu-Ray... it can be used, albeit slowly, with a USB 2.0 connection, but works decently with eSATA or USB 3.0.

For the big stuff, the relatively cheap price per TB of the LTO-6 drive is useful. However, not everyone can spend about $6000 for the drive, I/O card, and a decent server that can run it.

Re:News flash

[TheloniousToady]

FWIW, I did a little quick research on Amazon and came up with the dollars/GB of various media as shown below:

Compact Flash: $1.06 / GB
SSD: $0.68 / GB
HDD: $0.04 / GB
Blu-ray: $0.04 / GB
DVD: $0.08 / GB
Data tape: $0.02 / GB

This suggests that flash media would need to come down in cost by more than a factor of 20 to be competitive with HDDs and cheaper media. Also, Compact Flash seemed to be more expensive per GB than SSDs.

Although flash prices may drop, other media likely will also, so a relative drop by a factor of 20 seems unlikely. Factors other than cost may be a consideration, but if I were running things at Facebook, it would be pretty hard to pay 20x as much per GB just to save space.