The table below shows a schedule where each weekday tape accumulates all files that changed since the beginning of the week (or the initial level 0 for the first week), and each Friday's tape contains all the files changed that week.
Table 42-9 Daily Cumulative/Weekly Incremental Backup Schedule
Floating |
Mon |
Tues |
Wed |
Thurs |
Fri |
|
---|---|---|---|---|---|---|
1st of Month |
0 |
|
|
|
|
|
Week 1 |
9 |
9 |
9 |
9 |
3 |
|
Week 2 |
9 |
9 |
9 |
9 |
4 |
|
Week 3 |
9 |
9 |
9 |
9 |
5 |
|
Week 4 |
9 |
9 |
9 |
9 |
6 |
The table below shows how the contents of the tapes can change across two weeks using the previous schedule. Each letter represents a different file.
Table 42-10 Contents of Tapes for Daily Cumulative/Weekly Incremental Backup Schedule
Mon |
Tues |
Wed |
Thurs |
Fri |
|
---|---|---|---|---|---|
Week 1 |
a b |
a b c |
a b c d |
a b c d e |
a b c d e f |
Week 2 |
g |
g h |
g h i |
g h i j |
g h i j k |
With this schedule, you need six tapes (if you want to reuse daily tapes), or nine tapes (if you want to use four different daily tapes): one for the level 0, four for the Fridays, and one or four daily tapes.
If you need to restore a complete file system, you need the following tapes: the level 0, all the Friday tapes, and the most recent daily tape since the last Friday tape (if any).