Recently we have installed SQL Server 2012 Web edition (64 Bit) in Windows server 2012 Std edition (64 Bit). The Windows server having 8GB of memory.That server is mapping with an alert tool (which is crossing the threshold memory of 80%).
Actually the problem is most of the time, the windows task manager is showing as SQL Server taking 85% to 95% of memory(Even though there is no much operation). So that the alert tool keep on sends the alert.
Now, how can I find that SQL server is really taking the much memory?
Should I configure the minimum server memory and maximum server memory option in SQL Server?
What you are observing is the expected behavior of SQL Server. SQL Server manages its own memory. So, after you start up the server, it will request more and more memory from the OS as and when it needs, until it reaches the maximum setting. If it does not need the memory anymore, it won't release the memory back to the OS. It will hold on to that, so it can use/manage that for future activities.
What you should do is to set the maximum memory to some value you are comfortable with. On a dedicated server, leave about 2 GB for the operating system. So if your 8GB Windows Server is a dedicated server, set the maximum memory to about 6GB or 6.5GB. You can do this while the server is running; no restart required. The memory consumption may not come down immediately, but it will come down eventually.
You can set the maximum memory in the Memory tab of the Server Properties dialog (right-click on the Server name in SSMS to get that dialog). Be sure to observe that the number you set there is in MEGABYTES, not gigabytes.