Hello Shanmuga,
1: See the following documentation page for setting up DR DB auto-restart.
Complete the Post-Installation Configuration - CA Performance Management - 3.6 - CA Technologies Documentation
2: This Knowledge Base Article shows how to restart each server in a CAPM environment. It shows the proper order and steps for each server on it's own.
How to properly restart the CA Performance Managem - CA Knowledge
In terms of system restart order, first should be the DR DB. Once it's running restart the DA and then the DC services. The DA won't start without a running DB to connect to. The DCs won't start if they fail to connect to a running DA.
PC can be stopped/started independent of the others.
3: There aren't any environment variables that need to be loaded or anything like that for CAPM environment servers. If using a sudo user to install and run the software the configuration of each sudo user can vary per server.
Sudo user configuration for CA Performance Center:
Prepare to Install Performance Center - CA Performance Management - 3.6 - CA Technologies Documentation
Sudo user configuration for CA Data Aggregator:
Prepare to Install the Data Aggregator - CA Performance Management - 3.6 - CA Technologies Documentation
Sudo user configuration for CA Data Collector:
Prepare to Install the Data Collectors - CA Performance Management - 3.6 - CA Technologies Documentation
Sudo user configuration for CA Data Repository running the Vertica DB:
Prepare to Install the Data Repository - CA Performance Management - 3.6 - CA Technologies Documentation
Let us know if that answers your questions.
Thanks,
Michael