Table 33-11 shows a schedule where each weekday tape contains only the files changed since the previous day, and each Friday's tape contains all files changed since the initial level 0 at the beginning of the month.
Table 33-11 Daily Incremental/Weekly Cumulative Backup Schedule
Floating |
Mon |
Tues |
Wed |
Thurs |
Fri |
|
---|---|---|---|---|---|---|
1st of Month |
0 |
|
|
|
|
|
Week 1 |
3 |
4 |
5 |
6 |
2 |
|
Week 2 |
3 |
4 |
5 |
6 |
2 |
|
Week 3 |
3 |
4 |
5 |
6 |
2 |
|
Week 4 |
3 |
4 |
5 |
6 |
2 |
Table 33-12 shows how the contents of the tapes can change across two weeks using the previous schedule. Each letter represents a different file.
Table 33-12 Contents of Tapes for Daily/Weekly Cumulative Backup Schedule
Mon |
Tues |
Wed |
Thurs |
Fri |
|
---|---|---|---|---|---|
Week 1 |
a b |
c d |
e f g |
hi |
a b c d e f g h i |
Week 2 |
j k l |
m |
n o |
p q |
a b c d e f g h i j k l m n o p q r s |
With this schedule you will need at least nine tapes (if you want to reuse daily tapes--not recommended), or 21 tapes (if you save weekly tapes for a month): one for the level 0, four for the Fridays, and four or 16 daily tapes.
If you need to restore the complete file system, you will need the following tapes: the level 0, the most recent Friday tape, and all the daily tapes since the last Friday tape (if any).