Antsle's file system is based on ZFS which include powerful features to speed up your servers. It creates a very fast cache located in the server’s memory (RAM), called an ARC cache. The size of the ARC cache can range from 30% - 90% all of unused RAM. It is released back to your antlets as soon as it's needed for other applications. ZFS prioritizes the content that is both used most frequently and common across your virtual machines (for example, if you have many antlets based on a single template). This speeds up as many of your antlets as possible.
With the ARC cache your servers run faster but your RAM can look like it is always near MAX utilization. We are currently working on an update that will allow us to dynamically determine the amount of RAM being utilized for the ARC cache and deduct that from the total so you see your "true" RAM usage.