Proponents of tape over disk backup point out disks can't be removed and stored off site whereas tape cartridges can. That means a disk-based backup protection scheme can't protect you against events that effectively destroy your IT facility or servers.
This can't be denied.
But we can wonder if it's an aspect of tape that might not be that much used in practise. For, of course, the further away a tape cartridge is the more inconvenient it is to restore the data on it.
You also have to transport the tape out of the IT room. Generally it will be stored in a fire-proof cupboard. Only big businesses or ones with special needs will store some of their tapes in distant vaults.
For everyday businesses we might ask if the fact that tapes are stored in cupboards is not an after-the-fact thing rather than a designed-in tape protection strategy. Storing dozens, even hundreds of tapes in the IT room is not a problem physically unless you have lots of the darn things. Rows of them on shelves are quite a common sight in some IT facilities.
It's an interesting aspect of this tape-vs-disk argument that it is weakened when we consider tape libraries. These contain thousands of tape cartridges and are located inside IT facilities and therefore just as vulnerable to disasters that destroy IT rooms.
I think we might take a pause for thought and ask if the ILM concept applies to tape backup data as well as to data generally? Not all tapes are equal.
Some are needed for short-term restore - a timescale of minutes, hours, days and weeks. Some are needed for medium term restores - a timescale of months, and some are needed for the long term - a timescale of years.
Depending upon the amount of data involved then off-site data storage could be achieved either by shipping tapes or by a network link to a remote site.
The restoration needs will have a large say in where the tapes are stored. No-one is going to store tape data needed for restoration in minutes, hours or days in an off-site vault.
If they are stored in the same building as the IT facility then what real disaster protection do you have? You may as well store the data on disk and enjoy radically faster restoration and the same, limited, level of disaster recovery protection. You are no worse off in that regard.
We can agree to the assertion that 'tape is not dead' and another one that 'there will always be a need for tape' but we can also understand that the area of data protection where tape is the best medium to choose is now under debate, vigorous debate at that.
The rise of D2D alternatives is prompting us to think much more clearly about the role of tape in data protection and why we actually do certain things with tape.
You might carry on the with your existing tape way at the end of such analysis and question-asking. Equally you might decide that disk is preferable for some if not many aspects of data protection and retire tape to a smaller area of your protection needs.
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