Tape drives remain leading technology used by organizations for backup and archiving. However, plethora of tape drives on market can make choosing appropriate tape drive a confusing task. How do you select a tape drive that satisfies your needs without blowing budget? The following are just some of main factors to consider.
Select a tape drive that has sufficient capacity to store your backups. Tape drives are able to compress data so that more data may fit on tape, which is why manufacturers specify both a native capacity and a compressed capacity, usually with a compression ratio at 2:1. However, highly-compressed files such as those in video and sound formats are hardly compressible at all. For this reason, do not heed specified compressed capacity when choosing a tape drive.
A good way to determine size of backup job after compression is to study logs of past backups. If these are unavailable, it is safe to assume that data can be compressed at a ratio of 1.4:1, unless hard drive contains an usually large number of highly-compressed files.
2. Transfer rate.
The transfer rate of tape drive is becomes important when there is limited "window of opportunity" in which backup jobs may run. It is often desirable for backups to take place during night when network use is at its lowest. Select a tape drive that is capable of completing a backup job within your window of opportunity. For instance, to back up 400GB per night, you will require a transfer rate of about 30GB/hour.
A little known fact about tape drives is that data must be supplied to them at a sufficient rate in order to keep them streaming, or else tape suffers from start-stop motion. This motion severely degrades life of drive and tapes and reliability of backups.