Service manual

Optimizing For Searches
118 Sun ONE Directory Server Installation and Tuning Guide • June 2003
3. Reads from and writes to the database files when import cache runs out.
Directory Server may also write log messages during suffix initialization, but
does not write to the transaction log.
Tools forsuffix initialization such as
ldif2db (/usr/sbin/directoryserver
ldif2db
) delivered with Directory Server provide feedback concerning cache hit
rate and import throughput. Having both cache hit rate and import throughput
drop together suggests that import cache may be too small. Consider increasing
import cache size.
Optimizing For Searches
For top performance, cache as much directory data as possible in memory. In
preventing the directory from reading information from disk, you limit the disk
I/O bottleneck. There are a number of different possibilities for doing this,
depending on the size of your directory tree, the amount of memory available and
the hardware used. Depending on the deployment, you may choose to allocate
moreor lessmemory toentry and database cachestooptimizesearchperformance.
You may alternatively choose to distribute searches across Directory Server
consumers on different servers.
All Entries and Indexes in Memory
Imagine the optimum case. Database and entry caches fit into the physical memory
available. The entry cache is large enough to hold all entries in the directory. The
database cache is large enough to hold at minimum all indexes. In this case,
searches find everything in cache. Directory Server never has to go to file system
cache or to disk to retrieve entries.
In this case, ensure that database cache can contain all database indexes even after
updates. When space runs out in the database cache for indexes, Directory Server
must read indexes from disk for every search request, severely impacting
throughput. Directory Server Console displays hit ratios and other useful
information under the Status tab as shown in Figure 6-5.