Server Memory Consumption Issue Need Help!

My Server Consuming memory as the server up-time goes up
earlier it use to run on 8GB of memory without restart for almost 2-3 days
but now we have 16GB of memory and the memory consumption reaches to 90% within 4-5 hrs of up-time and needs a restart to free RAM!
we have only one main server and a test server i.e only two servers
Server Specifications :

Can anyone guide me what could be the issue for high memory consumption?

I’m having this issue on a 64GB RAM Linux server aswell.

is it normal or could be some programming issue?? because i don’t think its normal or may be i don’t have much knowledge on it.
what do you say??
@dividerz

Show your server .cfg