Offsite mirroring of data on critical IT systems is great! No more loading and unloading of tapes. No more remembering to send tapes offsite and bring them back at the right time. And, depending on the method of mirroring employed, the data on the backup system can be bang up to date and/or restored almost instantaneously.
But there’s a small point that is sometimes overlooked. If you ever need to invoke the backup system in the event of a problem with the primary, how do you then back it up? Unless you have a second mirror of your data, or can set one up extremely quickly post-invocation, the data on your now live system is at risk.
So don’t consign the humble tape backup to the scrap heap. While you might not want to do tape backups as well as mirroring, at least consider maintaining the ability to do them, so they can be switched back on if needed. And by the way, don’t forget to test them periodically to make sure they still work.