591.Which type of backup must be performed first with an incremental backup?
A. Level 1
B. Level 0
C. Level 2
D. Level 3
Answer: B
RMAN can create multilevel incremental backups. Each incremental level is denoted by a value of 0 or 1.
A level 0 incremental backup, which is the base for subsequent incremental backups, copies all blocks containing data.
You can create a level 0 database backup as backup sets or image copies.
The only difference between a level 0 incremental backup and a full backup is that a full backup is never included in an incremental strategy.
Thus, an incremental level 0 backup is a full backup that happens to be the parent of incremental backups whose level is greater than 0.
增量备份参考： http://blog.csdn.net/rlhua/article/details/11763453
增量累积备份参考：http://blog.csdn.net/rlhua/article/details/11763671