Storage estimate for caching all data
For installation planning purposes, you can use an initial size estimate of a group buffer pool that caches read-only pages with changed pages (GBPCACHE(ALL)).
Calculate the sum of the local buffer pool storage for this buffer pool number (virtual only) across all members in the group. Then, multiply this amount by one of these workload factors:
| Factor | Condition |
|---|---|
| 50% | Less than half of the table spaces, indexes, or partitions specify GBPCACHE ALL |
| 75% | Half of the table spaces, indexes, or partitions specify GBPCACHE ALL |
| 100% | 75% of more of the table spaces, indexes, or partitions specify GBPCACHE ALL for a high sharing environment |
Example
Assume that the local buffer pool storage on all members of the group adds up to 200 MB. Half of the page sets that come into the pool are defined as GBPCACHE(ALL). The following calculation is an estimate for the size of a group buffer pool when GBPCACHE(ALL):200 MB x 75% = 150 MB