Looking for longlife storage solution - is tape still an option?

Question

hi there,
im looking for a long life and very safe way for backing up 6 TB of data.
is the magnetic tape option reliable? or what would u suggest to go for?
thx
manuel

Answer 1

Tape is still very much a viable option, and is used regularly to backup petabytes of data on a daily basis.
At that capacity there are basically three different formats to consider, AIT (developed by Sony), LTO (from IBM/HP), and SDLT (from Quantum).
Of the three, LTO offers the highest speed and tape capacity with an LTO3 tape holding 400GB native (800GB at 2:1 compression) and a speed of 80MB/sec.
Behind that comes SDLT-II at 300GB per tape and 36MB/sec (the newer, bleeding-edge SDLT-III drives run 800GB per tape at 60MB/sec).
Trailing the list comes AIT at 200GB per tape and 24MB/sec.
Clearly, to manage terabytes of storage you need more than one tape, which is where autoloaders and libraries come into play - a chassis that contains multiple tapes and some robotic mechanism that transports the tapes from their storage bin to the tape drive mechanism itself. Larger units support multiple drive units in the box and potentially hundreds or thousands of tapes.
As for interface, SCSI is the predominant interface for tape backup, although Fiber Channel is sometimes an option.
There are FireWire options, too, but this is unlikely to be viable for your volume of data.
As for vendors, consider Quantum, Overland, Exabyte and ADIC.
Of the vendors mentioned, ADIC are probably the best at the high-end with Overland my preferred mid-level systems, and Exabyte at the lower end.
You should look at your data to decide a backup strategy before you go much further, though. Even though you have 6TB of data, you may find that once you have that backed up you only have a few hundred megabytes or gigabytes of data that changes frequently. Any decent backup software system will manage this for you, taking some of the pain out of knowing which tapes are needed when it comes to restore.
On that basis you may be able to leverage a lower-end tape library to manage the smaller amount of daily backup load rather than a 10TB monster capable of backing up your entire data set in an hour.
Also, when it comes to backup strategies, consider the value of a disk-to-disk-to-tape system (D2D2T). These systems backup data very quickly to disk-based storage and then backup the disk-backup to tape. This reduces the time it takes to backup the critical data and also means that recent changes can also be restored from disk, without the overhead of loading the correct tape and reading the data from there.