Basic tuning mode

You can use the performance tuning tool to run basic tuning on a directory server with the existing server statistics.

In the basic tuning mode, the idsperftune tool tunes the following server components:

LDAP caches

The LDAP caches include entry cache, filter cache, group member cache, and group member cache bypass limit.

DB2® buffer pools

These include IBMDEFAULTBP and LDAPBP.

The basic tuning mode suggests the optimum tuning values for LDAP caches and DB2 buffer pools. The tool also updates the LDAP cache and DB2 buffer pool parameters with the values that are determined. These recommendations are based on the following inputs:

Amount of free system memory (%) to allot to a directory server instance

It specifies the total memory that is allocated to an instance. This value is also used as an input to the tool when you tune the size of entry cache, filter cache, and group member cache. If a value is not specified, when idsperftune is run the default value of 90% of system memory available is allocated.

The number of entries and the average size of an entry that is in a directory server instance

The total number of entries that can be stored in a directory is used to estimate the required cache size.

Another value that is used as input for the tool is the average size of an entry in bytes.

The average size of an entry and the total number of entries are used by the idsperftune tool to calculate the total size of the directory. Based on these values, the size that must be allotted to the Entry cache and Filter cache are calculated.

Note: The idsperftune tool provides a parameter to calculate the total number of entries and average size of entries that are present in the directory. For example, if you run idsperftune with the -s parameter, the tool computes the total number of entries and average size of entries and logs the details in the perftune_input.conf file. If you do not provide the parameter, then the total number of entries is set to 10000 by default.

Update frequency:

You must specify whether frequent updates or only batch updates to run. If you specify frequent updates are expected, then the filter cache is set to 0. Otherwise, it is set to 1 KB.

Total number of groups to be cached:

You can tune this value by providing the approximate value for the total number of groups whose members must be cached. This value must be the number of groups frequently used. If not specified, the default value of 25 is set.

Average number of members in a group:

You can tune the total number of members within a group to cache. If the value is not specified, the default value of 25000 is set.

Server instance name:

The instance name is retrieved from the IDS_LDAP_INSTANCE environment variable. If the environment variable is not set, then the server instance name is set with an available directory server instance name. If more than one instance is available and no instance name is provided by the administrator, then an appropriate error message is generated.

When you run idsperftune with the -u parameter to update the configuration settings, the DB2 buffer pools IBMDEFAULTBP and LDAPBP are set to AUTOMATIC. The DB2 Self Tuning Memory Manager (STMM) dynamically adjust the sizes of the DB2 buffer pools when the DB2 buffer pools are set to AUTOMATIC. When you run the idsperftune tool, the memory size to allocate for LDAP entry cache is calculated. When you run the idsperftune tool in basic mode by providing the -B and -u parameters, the DB2 buffer pools are set to AUTOMATIC.

If the available memory can cache at least 80% of the entries, then 80% or more of total entries is cached in the entry cache. To override the default requirement to cache at least 80% of entries in LDAP entry cache, run idsperftune with the -E parameter and the target percentage of entries to be cached. For example, to cache a minimum of 50% of entries in the entry cache run the following command:

idsperftune -I instance_name -E 50

If the allotted memory is not enough to cache 80% of total entries, then the entry cache is set to a minimum value of 1000.