MTU Directory Server Performance Tuning Formulas
All settings here are based on information found in Sun ONE's Directory Server documentation. This documentation could be release notes, administration guides, etc. All references have been noted below when applicable.| Parameter | Formula | Description | sizelimit | N/A | Determines the number of entries the directory server will return to the requesting application when a search is performed. Ignored if bound as the directory super user. More information on tuning this parameter is available in the Sun ONE Directory Server Administrator's Guide. |
|---|---|---|
| idletimeout | N/A | Determines the amount of time the directory server will allow a connection to remain without it performing an operation. Useful if connected clients "forget" to unbind/disconnect. |
| timelimit | N/A | Determines the amount of time the directory server will spend on an operation. Can improve performance if timelimit is reduced such that only fast operations are completed. Mostly useful on replicas that should be used for quick searches. |
| lookthroughlimit | N/A | Determines the number of entries the directory server will look through on a search in order to find a match for the specified search criteria. When set to a low number performance improves since searches that require a large amount of entries to be looked through are rejected quickly. |
| allidsthreshold | Ideal: (Number of Entries) * 5% Minimum: (Number of Entries) * .5% Maximum: (Number of Entries) * 50% |
The allidsthreshold parameter is used to increase performance when searching the directory server. The formulas are used to tune this parameter to an appropriate value given your situation. More information on tuning this parameter is available in the Sun ONE Directory Server Administrator's Guide. |
| dbcachesize | During Import ((Free System Memory) / 2) - 1 = size in MB During Normal Operation (((Free System Memory) / 2) - 1) - cachesize - "safety space" = size in MB where "safety space" is the amount of memory, in MB, that you would like to have as a safety net for the system. Currently set to 2 Gigabytes. |
The dbcachesize parameter is used to increase performance for all operations. It can have a profound impact when importing data and should be increased when importing data. It should never be set larger than the available system resources. More information on tuning this parameter is available in the Sun ONE Directory Server Administrator's Guide. |
| cachesize | (Amount of spare memory, in bytes) / (~size of entry, in bytes) = Number of entries that fits in cache, rounded down | The cachesize parameter specifies the amount of memory dedicated to the entry cache. This parameter can increase search performance if set properly as cache hits will increase. More information on tuning this parameter is available in the Sun ONE Directory Server Administrator's Guide. |
| db_idl_divisor | set to 4 for more than 100,000, but less than 1,000,000 entries set to 8 for more than 1,000,000 entries |
Not much information on this one, but it's used to improve write performance for attributes that are substring indexed. The reference for this parameter can no longer be found on a reliable site. |
References
Sun ONE Directory Server Documentationdb_idl_divisor information - This site may no longer exist.
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