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Archiving Images and Data
Larry F writes:
Is the Sony ODS-D77U Optical Disc Archive a good option for long term storage of my digital images?
The Sony ODS-D77U is $3000 off as this was written. It’s a big initial investment for the unit, but the storage costs are quite appealing on a per-gigabyte basis (see discussion below under Capacity).
The Sony ODS-D77U can be used in in WORM mode (write once, read many) or with rewriteable media. Applicability vs workflow, cost, longevity, capacity vs data growth and more are all issues to consider. MPG has no experience using this type of unit, but being clear on the goal is a key first step: is the goal archiving or backup or both?
Archiving vs backup
For backup purposes the goals may be significantly different than for archiving. Backup is for protecting against relatively short-term drive failures; archiving is a long term consideration with issues of physical integrity and “bit rot” (see also IntegrityChecker). Be clear on the actual goals when choosing a solution.
For archival purposes, there are hardware and software considerations: how long do the discs last, but more important: will a device and software to read them exist in 5/10/20/50 years or whatever? This is a difficult area, with the safest bet being use of the most common disc formats. The BluRay of today could be the 8" floppy disc of 20/30/50 years from now. Will today’s BluRay discs or Sony cartridges be that 8" floppy disc 20/50 years from now? It that even the goal for most of us?
It is MPG’s view that every decade or so, it is wise to re-evaluate the medium upon which archived material is stored, possibly re-archiving all material onto new media (not necessarily dispensing with the old, but as an “insurance policy”, getting all material onto something more current).
Capacity
The Sony ODS-D77U offers write-once (WORM) cartridges up to 1.5TB and rewriteable cartridges from 300GB - 1200GB. High capacity is generally a plus since quite a lot of images or data can be written with little wasted space. Ditto for rewriteable vs write-once (WORM). For single photographers, it might be that months go by before the cartridge fills up, so the protocol must necessarily involve swapping, say, three cartridges onsite/offsite so as to have data safely away from the working system. For teams and groups, it might be that having high-capacity archival and semi-archival storage as backup is a big win, with disks rapidly filling up and conventional backup used together with the archival system.
A much lower cost and archival alternative that individuals may find appealing would be 25GB M-DISC cartridges, burned in a BluRay burner like the OWC Mercury Pro BluRay Burner. With BluRay discs, the entire disc is burned, so burning a disk for 4GB or 12GB or similar is relatively expensive on a per GB basis. But if the goal is to backup a photography shoot or similar so as to archive it offsite, the smaller but cheaper discs may be a good fit for a burn-and-store procedure following an important job. It may also be a good fit for critical business data every quarter or year or so on. Also, two of three copies could be burned when the work is particularly important, and stored separately. If the data is relatively small, ganging up new data (such as photography shoots) may mean burning discs once a week and/or whenever there is ~25GB to be archived makes sense (25GB to fill up an M-DISC capacity).
Unlimited cloud storage may be a valuable complementary solution, provided that a very fast internet connection is available. But such storage is more of a backup nature than an archival solution.
Performance
For nearline fast storage, MPG would prefer something like the OWC Thunderbay 4 RAID-5 edition. RAID-5 is fault-tolerant and willhandily outperform an optical storage device. While not archival, nearline archival solutions do not protect against physical threats such as theft or fire, so this implies offsite backups anyway: an offsite storage protocol would be needed in any case, along with a disciplined daily backup strategy.
Software, support, etc
MPG is not keen on custom software from a specific vendor, particularly software that requires a serial number, and particularly for archival use. Support is another issue, OS compatibility another, ease of use and reliability still more. These factors are much harder to evaluate, because they are not fixed, changing over time, and generally not for the better.
Marco B writes:
I want to alert your readers about a few things that that Sony ODS-D77U. We have used them at work for archiving and backup dailies for our productions for almost for a year and a half.
1- There is a limit of 60,000 files each storage tape (if I’m not wrong, check the manual)
2- The write speed with verification is SLOW, the read is ok. When I need to archive 1TB it takes like 8 to 9 hours to backup, and this because I’m sending not so much files.
3- Please be very careful to buy the new model, there’s two models, the first one has a mechanic problem that from time to time: the recording media jams inside, and it must be sent back to Sony or any official support to repair it. Sony claims the new one does not have that problem, but they don’t feel responsible for selling the old and not stating this PROBLEM to the customer. We’ve learned the hard way.
MPG: great feedback!
A limit of 60,000 files immediately makes the unit unusable for general use for me: even excluding mail and many other things, my work folder has 240,000 files. Slow backup speed is highly unappealing also; it discourages backups. See notes above on Performance. Taken together, those kind of limits tend to make it a specialty solution.
