Ability to change the Directory Server's maximum DB cache size by manually editing the slapd.ldbm.conf  file.

  Factoid:

The two most important things you can do to improve Server performance are to increase the size of the cache and reduce the number of indexes to just the ones you really need.

Try This:

Change the value of the dbcachesize parameter to 8,000,000 using a text editor.

Chapter 10 of the Directory Server Administrator's Guide.

Maximum DB Cache Size

This parameter specifies the size in bytes of the in-memory cache.  Increasing this number uses more memory but can substantially improve server performance, especially during modifications or when the indexes are being built. Do not increase this number beyond the available resources for your machine.  The default value for this parameter is 10,000,000. 

Here are some simple steps for establishing the value for this parameter: 

  • Identify the amount of free memory available when your system configuration is operating normally (use system monitoring tools).
  • Take 75% of your free memory and then 75% of that value.  The first 75% gives you the memory available for your database cache.  The second 75% is the value you use for the dbcachesize. 
  • Regardless of the free memory available, the database cache should never exceed 2 GB. 
Here's an example: 
  • Free memory  150 MB 
  • Memory available for database cache 0.75 * 150  = 112 MB 
  • Value for dbcachesize 0.75 * 112 = 84 MB 
It is important that you do not set the dbcachesize to the total amount of free memory. This is because when you set the dbcachesize to some value, the server will actually use as much as 25% more than that value because of the overhead required to manage the cache.  That is the reason the dbcachesize value in the example is set to 84 MB and not 112 MB.

You can use the GUI or the monitor command line tool to verify the actual memory usage of the database cache.  One of the monitor tool attributes is the number of pages in use in the database cache. Multiply that number by the default page size of 8 KB to estimate your database cache memory usage.  If you are running the directory server on Solaris, your page size may actually be different.

slapd.ldbm.conf

 
The default location of this file is c:\Netscape\Server4\slapd-directory on NT systems.

You can click on this icon to see an example of slapd.ldbm.conf.
 

Changing Maximum DB Cache Size

To change the value for maximum DB cache size:
  • Locate the slapd.ldbm.conf file
  • Use a text editor to search for the dbcachesize parameter
  • Replace the default value with the new value you've chosen
  • Restart the Directory Server using the Admnistrative window in Netscape Console
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