Databases Reference
In-Depth Information
How It Works
Sizing a fast recovery area is simple in concept. Decide on a backup strategy. Work through each file type to determine
how much fast recovery area space each file type needs. Add everything up. Allocate that amount of space. The key to
success is to carefully think through the details.
By the way, in this recipe we have assumed that the fast recovery area to be sized will be used for only one
database. If you have more than database to back up to the same area, calculate the space for each database, and sum
the resulting values to arrive at a size that will suffice for a combined fast recovery area serving all the databases.
Tables
3-7
through
3-9
show several working examples of our sizing worksheet. There's one example for each of
the three backup strategies that we listed earlier in the solution section. Our file sizes and counts won't match yours,
of course, but you can see how the different values in the worksheets ultimately lead to a size recommendation for the
fast recovery area.
Table 3-7.
Sizing the FRA for Regular RMAN Backup
Type
Size per File or Set
Total per Cycle (Week)
Total
Description
Full backup set
2,500
2
5,000
We need 2 Level 0 backups per
cycle, that is, a week.
Image copies
0
0
0
We take RMAN backup sets in this
option, so this is not required.
Archived redo logs
100
2
200
Two days' worth of archived redo
logs backup.
Incremental copy of
the data files
200
6
600
Control file auto
backup
0.2
7
1.4
Total space required
5,801.40
Table 3-8.
Sizing the FRA for RMAN Image Backup
Type
Size per File or Set
Total per Cycle (Week)
Total
Description
Full backup set
0
0
0
We use image copies, so this is zero.
Image copies
3,000
2
6,000
We need 2 Level 0 backups per
cycle, that is, a week.
Archived redo logs
100
2
200
Two days' worth of archived redo
logs backup.
Incremental copy
of the data files
200
6
600
Control file auto
backup
0.2
7
1.4
Total space required
6,801.40
