Target Skill:

After reading this page you will be able to change the maximum number of entries in your Server's cache.

     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     


  Factoid:

The 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

     
References:

Directory Server Administrator's Guide: Chapter 10
 

Maximum Entries in Cache

 
This parameter specifies the number of entries the directory server will maintain in the entry cache. The default value for this parameter is 1,000.  Increasing this number uses more memory but can substantially improve search performance. The actual amount of memory required per additional entry depends entirely on the nature of the data you choose to store in the Directory Server.

While bigger caches are usually better, performance can degrade if dbcachesize is set too large.  If you set the database cache too large and exceed the physical free memory available, the process will begin to thrash virtual memory as it writes clean and dirty pages to disk. The result is severe performance degradation.  You can detect this behavior by using one of the system monitoring tools such as vmstat that provides statistics for virtual memory usage. 

The sample entry below containing person information for Sam Carter is 387 Bytes. 

dn: uid=scarter, ou=People, o=airius.com 
cn: Sam Carter 
sn: Carter 
givenname: Sam 
objectclass: top 
objectclass: person 
objectclass: organizationalPerson 
objectclass: inetOrgPerson 
ou: Accounting 
ou: People 
l: Sunnyvale 
uid: scarter 
mail: scarter@airius.com 
telephonenumber: +1 408 555 4798 
facsimiletelephonenumber: +1 408 555 9751 
roomnumber: 4612 
userpassword: sprain
The Directory Server can retrieve data from the entry cache as much as twice as fast as it can retrieve the same data from the database cache.  Therefore, you will achieve the fastest directory search performance when all requests are delivered from the entry cache.  The actual magnitude of the performance benefit depends on the complexity of your search and the type of indexes you maintain. 
 

Tuning the entry cache

You should consider increasing the size of your entry cache if the following are true: 
  • You have memory to spare

  •  
  • You use the monitor tool and find that by increasing the entry cache size, you increase the cache hit ratio 

Changing The Maximum Entries In Cache

1.  From the Server Manager go to Server Preferences |Performance Tuning

2.  Change the desired value. 

3.  Click OK. 

4.  Click Apply. 

5.  Click Apply Changes. 

6.  Stop and then restart the Directory Server. 


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