DT_HOME refers to the AppMon installation directory. It could be referenced as %DT_HOME% on Windows or $DT_HOME on *NIX or generically <DT_HOME>
It originally refereed to the environment variable that is optional now and can be used for convenience and then should point to the AppMon installation root, for example
C:\Program Files\dynaTrace\dynaTrace 7.0 for a default 64-bit AppMon installation on Windows.
The bootstrap part of an Agent tries to save the core into a subdirectory
agent/downloads for the following directories in the following order:
DT_STORAGE, if not set:
DT_HOME, if not set:
DTD_HOME (precursor of
DT_HOME), if not set: path of the Agent,
tmp, current directory
So, if no environment variable is set you are perfectly fine, because write permissions to
agent/downloads were set at install time. If all fails, updates are not available.
When you set DT_HOME you can use it to construct the path in the Agent connection string. For example, instead of