Quick one today:

Recently, in our lab, we ran into this interesting error:

Turns out, we were attempting to multiple operations there were mutually exclusive. For example,

• Adding a new data file while backup operation is running
• Removing data file while running backup operation
• Shrink file during backup operation
• etc.

Once the backup is completed, we were able to perform these operations. When backup runs, it reads every extent and writes into a backup file. So, during this, any attempts to change the underlying file structures (where the extents live) could not be allowed (obviously).

There may be several such operations that are mutually exclusive; So it is good to learn and list them so we do not do this again. More will be added as they come up.