Set up the AppMon Server

Memory settings

You configure memory settings in the AppMon Client at initial startup. After importing a license you can select them from a list of predefined deployment sizes.

Change the selected deployment size at any time after initial setup by choosing Settings > Dynatrace Server > Settings > Sizing or directly under -memory in DT_HOME/dtserver.ini. Find more information in Sizing Settings.

Additional considerations and troubleshooting

Versioned profiles

All System Profiles are stored in the profiles folder as XML files (ending with .profile.xml). Those files should not only be backed up on a regular basis but can also be archived with common version control systems. Doing so provides easy history control and rollback over the course of time.

Parallel startup of server and analysis server

If you have the AppMon Server and AppMon Analysis Server installed on the same machine (sharing the same core executables), it is not possible to start both servers at the same time, for example by using a Unix shell script.

In this case, there are two possible solutions:

  • Install the Analysis Server standalone on the machine.
  • In your shell script, first start the Analysis Server, wait a short time (typically 10 seconds is sufficient), then start the AppMon Server.

Number of open files limit on Linux

Some Unix-based systems impose a rather low limit on the number of files or file descriptors a user or process can have open. This limit includes open socket connections.

Because the AppMon Server needs to read/write many files from/to the session store and have many socket connections open, the system default limits for the number of open files may be too low. Some Linux distributions use a default of 1024 file handles, which is most likely too low for medium to large AppMon installations. Therefore, the AppMon server enforces a minimum of 2048 file handles. Use ulimit -n to query the current number of file handles.


Don't confuse the ulimit (thousands) with the system-wide limit (hundreds of thousands) that you can check with more /proc/sys/fs/file-max.

You may learn of an insufficient limit through an error message like IOException: Too many open files or Too many open files. Before changing anything, check the current (soft) limit with ulimit -n or ulimit -Sn. Use ulimit -Hn to determine how much you can raise it as non-root.

Use ulimit -n <numberOfFileDescriptors> to raise the (soft) limit temporarily for the current user. Add entries for other users / groups to /etc/security/limits.conf. Use ulimit -n to check that the change was successful.