The cms.exe
process stands for Central Management Server, it is one of the core pieces of the Crystal Server platform.
Why does cms.exe create so much connections against the database? can
it be limited?
If you open the CMC (Central Management Console) and select Servers and open the properties page for the Central Management Server, you should see an option System Database Connections Requested.
The option's purpose, explained by the Administrator's Guide:
Specifies the number of CMS system database connections that the CMS
attempts to establish. If the server cannot establish all of the
requested database connection, the CMS continues to function but at a
reduced performance, since fewer concurrent requests can be served
simultaneously. The CMS will attempt to establish additional
connections, until the requested number of connection is established.
what is their purpose?
Again, taken from the Administrator's Guide:
The CMS maintains security and configuration information, directs
service requests to servers, manages auditing, and maintains the CMS
system database.
In other words: your Crystal Server environment cannot function without the CMS. Shut it down and your whole environment stops working.
It always needs open connections to the database in order to serve requests quickly. While you can limit the number of connection, doing so might impact the performance of your Crystal Server environment.