The following table shows a schedule where each weekday tape contains only the files that 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 46–10 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 |
The following table shows how the contents of the tapes can change across two weeks with the daily incremental, weekly cumulative schedule. Each letter represents a different file.
Table 46–11 Contents of Tapes for Daily Incremental, 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 need at least nine tapes if you want to reuse daily tapes, which is not recommended. Or, you need 21 tapes if you save weekly tapes for a month: one tape for the level 0, four tapes for the Fridays, and four or 16 daily tapes.
If you need to restore the complete file system, you need the following tapes: the level 0, the most recent Friday tape, and all the daily tapes since the last Friday tape, if any.