Differential backups make perfect sense….backup only what has changed since the last Full backup. Differential backups dramatically reduce the storage needed to maintain backups, while lowering maintenance windows associated with Full backups. And, if managed properly, they do not add significant recovery time.
Here is an illustration of the Differential backup concept:
(Source: MSDN Developer Network)
That said, I bet there are many of you out there that hesitate to perform Differential backups because of some of the inherent risk that is involved. First, Differential backups require and rely on the last Full backup. If that last Full backup has been corrupted, deleted, or moved to an unknown location, the Differential backup is useless as it cannot be restored. After all, why do we perform backups? So, we can restore them when necessary. Another consideration is how much data has changed since the last Full backup. If lots of data has changed, it likely does not make sense to perform a Differential backup as you would no longer receive the benefit of time saved.
Enter Litespeed for SQLServer. It provides a powerful feature to address these risks…called Fast Compression. Think of it as intelligent Differentials. This patented technology performs checks ahead of the Differential backups. Fast Compression will first identify if the last Full backup exists and is valid. If it is successful, it moves forward with the Differential backup. If not, Litespeed will create a Full backup in its place. In addition, the Fast Compression feature checks to see how much data has changed. It compares this to a threshold that you can set. (the default value is 35%). If less than that amount of data has changed, it performs the Differential backup. If more data has changed than that threshold, it initiates a Full backup instead.
As a result, long database recoveries are virtually eliminated and data retention is protected.
Perform your SQLServer Differential backups with Litespeed’s Fast Compression feature and get peace of mind that your backups will be fast and reliable.