Sometimes, must restart tomcat to continue usergird server

[Thành Vũ Trung]

Hi all,
Anybody can help me know why sometime usergrid is not responding. I must
restart tomcat to continue. Pls give me recommend tomcat config if it's
possible.
My server details:
- Ubuntu 14
- Tomcat 7
- Usergrid 2.1.0

Thanks.
Thanh.