Memory; Disk Space; Networking - Sun Microsystems Sun GlassFish Enterprise Server 2.1 Tuning Manual

Server Scaling
the relative amount of time it spends in I/O versus CPU activity. Studies have shown that
doubling the number of CPUs increases servlet performance by 50 to 80 percent.

Memory

See the section Hardware and Software Requirements in the Sun Java System Application Server
Release Notes for specific memory recommendations for each supported operating system.

Disk Space

It is best to have enough disk space for the OS, document tree, and log files. In most cases 2GB
total is sufficient.
Put the OS, swap/paging file, Enterprise Server logs, and document tree each on separate hard
drives. This way, if the log files fill up the log drive, the OS does not suffer. Also, its easy to tell if
the OS paging file is causing drive activity, for example.
OS vendors generally provide specific recommendations for how much swap or paging space to
allocate. Based on Sun testing, Enterprise Server performs best with swap space equal to RAM,
plus enough to map the document tree.

Networking

To determine the bandwidth the application needs, determine the following values:
■
■
■
Then, the bandwidth required is:
N
peak
For example, to support a peak of 50 users with an average document size of 24 Kbytes, and
transferring each document in an average of 5 seconds, requires 240 Kbytes (1920 Kbit/s). So
the site needs two T1 lines (each 1544 Kbit/s). This bandwidth also allows some overhead for
growth.
The server's network interface card must support more than the WAN to which it is connected.
For example, if you have up to three T1 lines, you can get by with a 10BaseT interface. Up to a
T3 line (45 Mbit/s), you can use 100BaseT. But if you have more than 50 Mbit/s of WAN
bandwidth, consider configuring multiple 100BaseT interfaces, or look at Gigabit Ethernet
technology.
94 Sun GlassFish Enterprise Server 2.1 Performance Tuning Guide • January 2009
The number of peak concurrent users (N
The average request size on your site, r. The average request can include multiple
documents. When in doubt, use the home page and all its associated files and graphics.
Decide how long, t, the average user will be willing to wait for a document at peak
utilization.
r / t
) the server needs to handle.
peak