Unix Backup and Recovery

Ease of Administration

If a person is administering a relatively large backup system, the activities in the following list are performed all the time. How easy is it to do these things with the product you are considering?

Making duplicate volumes for off-site storage

This feature allows an administrator to make copies of volumes and send the copies off-site.^[36] The right way to do this is to copy from volume to volume, instead of running another backup. The more advanced products allow the copied volume to have its own identity. That way, the copied volume can be tracked in the catalog. (Older methods of copying volumes resulted in two copies of the same exact volume. The second volume never actually existed in the product’s database; it was just another copy of the first volume.) Some products also allow an administrator to specify the location of the copy volumes so that he will know which volumes are on-site and which volumes are off-site. That way, the software won’t ask for the volume that it knows is off-site, if it knows it has another volume on-site that has the same data on it.

Copying a saveset

There is a downside to copying volumes. Depending on the level of volatility of the data and the luck of the draw, the system may or may not fill up a complete volume each night. If copies are being made and sent off-site every day, what happens to the volume that is half full? If it is copied and sent off-site, the software cannot continue to write to the original volume, even ...