Memory limit

[Anand]

We have one big server that serves our rails web application. 

I'm new to using memcached and I'm planning to use it for storing session 
data, I mean as a session store. What happens if memcache consumes too much 
memory? Should I monitor the memcached process now and then and restart it? 
Or, can I set memory limits for it so that it won't exceed the allocated 
space?