Why tape migration?
There are a number of reasons why it makes sense to migrate tapes.
Tapes can store data for many years, decades even. But they don’t last forever, particularly if they’re not stored in a suitable environment. If, for example, the tapes are stored in a damp environment, the data can be wiped. As a result, they must be tested regularly to ensure they’re still in working order. If they are hard to read, you should migrate the data to avoid data loss.
Many legacy tapes also have outdated or rare formats. These tapes should be migrated onto more accessible systems, so the data is accessible if it’s needed quickly, for legal reasons for example.
Finally, if data is stored on tape hardware which is hard to maintain, it may be advisable to migrate it over to a newer backup environment.