A recovery cycle example when using image copies
Log management for a user group involves using image copies. You need to determine how often to make image copies.
Table 1 suggests how often a user group with 10 locally defined table spaces (one table per table space) might take image copies, based on frequency of updating. Their least-frequently copied table is EMPSALS, which contains employee salary data. If the group chooses to keep two complete image copy cycles on hand, each time EMPSALS is copied, records prior to its previous copy or copies, made two months ago, can be deleted. They will always have on hand between two months and four months of log records.
In the example, the most critical tables are copied daily. The Db2 catalog and directory are also copied daily.
| Table space name | Content | Update activity | Full image copy period |
|---|---|---|---|
| ORDERINF | Invoice line: part and quantity ordered | Heavy | Daily |
| SALESINF | Invoice description | Heavy | Daily |
| SALESQTA | Quota information for each sales person | Moderate | Weekly |
| SALESDSC | Customer descriptions | Moderate | Weekly |
| PARTSINV | Parts inventory | Moderate | Weekly |
| PARTSINF | Parts suppliers | Light | Monthly |
| PARTS | Parts descriptions | Light | Monthly |
| SALESCOM | Commission rates | Light | Monthly |
| EMPLOYEE | Employee descriptive data | Light | Monthly |
| EMPSALS | Employee salaries | Light | Bimonthly |
If you are using the BACKUP SYSTEM utility, you should schedule the frequency of system-level backups based on your most critical data.
If you do a full recovery, you do not need to recover the indexes unless they are damaged. If you recover to a prior point in time, you do need to recover the indexes. See Plans for recovery of indexes for information about indexes.