Are you using the tape library for data backups, data archives or both? What you are going to use the tape library for will determine where you need to start. Have you selected the software you will use to drive the tape library? You should ensure that your selected data backup, archive, hierarchical storage management (HSM), etc., supports the tape library you choose.
How much data will you be storing in the backup tape library? Tape libraries can be small, medium or large. Some can start off small, and grow with your needs in both the number of tape drives supported, and the number of cartridges that can be stored. Some will even allow you to remove cartridges from the library for offsite storage or long-term archive. Larger tape libraries will have robotic mechanisms for loading the tapes, and bar code readers to ensure the correct tapes are selected and loaded. Then there are virtual tape libraries (VTLs) that use disk-based devices that emulate the features of tape libraries and provide nearly online access speeds to backup or archived data. Again, your selected software will dictate the features and functions needed in the tape library.
What tape drives and media are supported? Today there are many different tape technologies and media types available. There are linear tape-open (LTO)-3, LTO-4 and LTO-5 tape drives from the LTO Consortium, Sun StorageTek's T9840, T1000A, T10000B and T10000C tape drives, IBM Corp.'s TS1120, TS1130, TS3592 and TS3593 tape drives, just to mention a few. The media can be normal capacity cartridges or high-capacity cartridges. Some older media can be read by newer generations of tape drives, but not written by these new drives unless the format on the media is changed, or perhaps not at all. Tape drives continue to evolve, and there is a limited shelf life for data written to a tape, so data archives must be migrated from old tapes to newer tapes every few years. You will want to ensure that your tape drives and media choices will be viable over many years.
What compliance standards are you required to meet? If write once, read many (WORM) technology is needed, you will need to ensure that your vendor provides devices and media that support it. Are there other requirements for your data like encryption, key management, secure deletion, or perhaps specific service-level agreements (SLAs) you must be able to meet? All of these choices will have an effect on the library you choose.
Finally, you may even want to consider products other than tape libraries. There are many virtual tape library and disk-to-disk (D2D) solutions available today that would better service your needs.
This was first published in February 2010