Hi Jeewan,
what you are describing sounds very familiar to me. DI Serer had ( still has ) some issues that lead to crash. Basically it is mostly memory leaks or database locks - have a look for that ( ~ 1.2 gb is critical, HANA : no idea how to find locks ). If you are able reproduce the problem, it is the best to contact support - they have some tools to monitor DIS.
regards,
Maik