Using the RAM Usage diagram you can get the data on when and why the ram usages were higher. Use this data to analyze and optimize the performance of your server. Here in the RAM tab, you will see there the following graph –

• Ram Usage – Random Access Memory(physical memory). Here this graph shows the use (in %) of your server RAM.
• Ram Buffers – Buffer memory is a temporary storage area in the main memory (RAM) that stores data transferring between two or more devices or between an application and a device. Buffering compensates for the difference in transfer speeds between the sender and receiver of the data.
• Swap Usage – Swap space in Linux is used when the amount of physical memory (RAM) is full. If the system needs more memory resources and the RAM is full, inactive pages in memory are moved to the swap space. While swap space can help machines with a small amount of RAM, it should not be considered a replacement for more RAM.