Auto starting DB2 under windows is no problem. The services are created when DB2 is installed. DB2 will automatically start when windows starts.
DB2 V9 was started through /etc/inittab entry, it was straight forward to set up automatic start. Unfortunately in RHEL 6 /CENTOS 6 inittab is deprecated.
DB2 V10.1 can handle
On Red Hat Enterprise Linux 6 (RHEL6) systems, the DB2 Fault Monitor Coordinator daemon (db2fmcd) is not restarted after a system restart. As a result, DB2 instances are also not restarted even if the instances are configured correctly to start automatically.
This technote https://www-304.ibm.com/support/docview.wss?uid=swg21497220 describes how to enable the fault monitor so that db2fmcd autostarts on RHEL6 systems.
Although this does not always resolve the issue as it should. Additionally this script below (copy of db2fmcd) to
/etc/init for each DB2 instance resolved the problem.