Estimating the size of the LICON data set

Before you create LICON data sets, you can estimate the required storage for the LICON data sets.

About this task

Two methods are available for estimating the LICON data set size. The first method is more complicated but results in a precise data set size. The other method is simpler, but results in only an approximate data set size. You can use the simpler estimation method if the number of database segments is less than 20.

Tips:

To accommodate any future increase in the number of databases, partitions, or DEDB areas, make the LICON data set size larger than the value that you calculate. For example, when you allocate a LICON data set, increase the calculated primary allocation size by 10% to 20%, and increase the secondary allocation size by approximately 10% of the primary allocation size.
When you create multiple LICON data sets, you can create them on the same volume or on different volumes.

Procedure

For each LICON data set, use one of the following methods to estimate the data set size:

Estimating the precise LICON data set size

Use the following formula to calculate the precise LICON data set size:

       LICON data set size = total_size_required_for_full-function_databases 
                            + total_size_required_for_HALDBs 
                            + total_size_required_for_DEDBs

total_size_required_for_full-function_databases

The total size of all the full-function databases that are to be processed.

For each full-function database, calculate the required size by using the following formula:

       (450 + 32 * number_of_DSGs + 52 * number_of_segments 
        + 180 * access_info_size) * 16

Note: DSG stands for data set group.

total_size_required_for_HALDBs

The total size of all the HALDB partitions that are to be processed.

For each HALDB partition, calculate the required size by using the following formula:

       (450 + 32 * number_of_DSGs + 52 * number_of_segments 
        + 180 * access_info_size) * 16

total_size_required_for_DEDBs

The total size of all the DEDB areas that are to be processed.

For each DEDB area, calculate the required size by using the following formula:

       (220 + 48 * number_of_segments + 180 * access_info_size) * 16

Notes:

If you do not enable the database access recording option (activated by the RECUPD, RECLD, or RECUL keyword in the global option module), access_info_size is 0. When this option is enabled, access_info_size increases by 1 for each keyword that you specify. For example, if you enable the RECUPD option (one keyword), access_info_size is 1. If you enable RECUPD and RECLD options (two keywords), access_info_size is 2.
Related reading: For instructions to activate this option, see Global option module generation macro.
For these formulas, the units are in bytes.
Each formula is multiplied by 16 for storing histories of database definitions.

Estimating the approximate LICON data set size

Use the following formula to calculate the approximate LICON data set size:

       LICON data set size = (32 * number_of_full-function_databases 
                              + 32 * number_of_HALDB_partitions 
                              + 16 * number_of_DEDB_areas) KB

number_of_full-function databases: The number of full-function databases (excluding HALDBs) that are to be processed.
number_of_HALDB_partitions: The number of HALDB partitions that are to be processed.
number_of_DEDB_areas: The number of DEDB areas that are to be processed.