Directory Proxy Server uses memory mainly to hold information that is being processed. Complex aggregations for processing some virtual directory requests against multiple data sources may temporarily use extra memory. If one of your data sources is an LDIF file, Directory Proxy Server constructs a representation of that data source in memory. However, unless you use large LDIF data sources, not a recommended deployment practice, a couple gigabytes of memory devoted to Directory Proxy Server should suffice. You might want to increase the Java virtual machine heap size when starting Directory Proxy Server if enough memory is available. For example, to set the Java virtual machine heap size to 1000 megabytes, use the following command.
$ dpadm set-flags instance-path jvm-args="-Xmx1000M -Xms1000M -XX:NewRatio=1"
This command uses the -XX:NewRatio option, which is specific to the Sun Java virtual machine. The default heap size is 250 megabytes.