Determining Memory Requirements
3-4 Oracle HTTP Server powered by Apache Performance Guide
■Memory for Non-HTTP Serv er Software and Operating Sys tem
■HTTP Server Memory Requirements
■JServ Memory Requirements
■Determining Java Heap Size
■Servlet and OracleJSP pages Memory Requirements
■Number of JServ Processes
Memory for Non-HTTP Server Software and Operating SystemIn an idle system with memory resources freely available, your operating system
statistics may indicate that the resident memory usage is close to the virtual size. As
users place more load on the system, the operating system reclaims unneeded
memory from these processes, and the amount of resident memory they consume
decreases. If you are monitoring your own system, take snapshots of processes at
varying usage levels.
Refer to your operating system hardware and software documentation for more
information on measuring and tuning operating system memory usage. You can
monitor memory usage and processor statistics with standard operating system
tools. See Chapter 2, "Monitoring Your Web Server" for more information.
HTTP Server Memory RequirementsIn a series of tests of listener memory usage, each HTTP listener used (at startup)
approximately 400K of resident memory. This size increased by 500-600K per
process when the listener was active. When it was dormant, the operating system
reduced the listener’s memory usage back to the startup size.
Using standard operating system tools, you can examine resident memory sizes. If
you look at a listener process, you will see that it is larger than the figure above
because the displayed size includes shared memory.
JServ Memory RequirementsA JServ process using JDK 1.2 requires 12-15 MB at startup. Using JDK 1.1.8, it
requires 10 MB.
Determining Java Heap SizeFor JDK 1.1.8, the default maximum heap size is 16MB. For JDK 1.2, it is 24MB.