Normally speaking, any time any change is made to a Backup Specification, no matter how small, the next Backup will be Full
I was not aware that this also applied to clustered servers that went through a Failover
Why are Incremental backups run as Full?
Full backups are performed instead of incrementals
You specified an incremental backup, but a full backup is performed.
There are several possible reasons for this behavior:
No previous full backup
Before performing an incremental backup of an object, Data Protector requires
a full backup as a base for comparison to determine which files have changed
and consequently need to be included in the incremental backup. If a protected
full backup is not available, a full backup is performed.
The description has changed
A backup object is defined by the client, mount point, and description.
If any of these three values changes, Data Protector considers it as a
new backup object and performs a full backup instead of an incremental.
Trees have changed
A protected full backup already exists but with different trees than the
incremental backup. There are two possible reasons for this:
You have changed the trees in the backup specification of the protected full backup.
You have created multiple backup specifications with the same backup object
but different trees specified for the backup object.
The backup owner is different
If your backups are configured to run as private, the user starting the backup
is the owner of the data. For example, if user A performs a full backup and
user B tries to start an incremental backup, the incremental backup will be
performed as a full backup. This is because the data for user A is private and
cannot be used as a base for user Bs incremental backup.
The same problem occurs if user A performs a full backup, then user performs
an object copy session, and the original is exported or overwritten.
User A cannot perform an incremental backup because the full backup (the copy)
now belongs to user B.
Enhanced incremental is not performed after the upgrade
This problem may occur on Windows, HP-UX, and Linux systems. If you upgraded
Data Protector from version A.06.11 or earlier, the old enhanced incremental
backup repository cannot be used with the new product version anymore.
Therefore, a full backup is performed. During a the full backup, a new
enhanced incremental backup repository is created