Wormly Metrics provides RAM usage monitoring - among thousands of other metrics.
RAM is often a strained resource in web servers, which must serve an unpredictable number of remote clients simultaneously. Executing complex web applications written in memory-hungry languages only exacerbates this.
Wormly monitors the RAM usage activity of your web servers, presenting the information collected in the following trend graph:
The trends of three key components are shown:
RAM Free. The amount of unallocated RAM available. Linux systems tend to keep this as low as possible; and do not free up the system's physical RAM until it is requested by another process.
Page & Buffer cache. RAM that is in-use for buffers and page caching, but hasn't been used recently so will be reclaimed first for use by a running process.
RAM used. RAM that has been used recently and will not be reclaimed unless we have insufficient Inactive RAM to claim from. In Linux systems this is generally the one to keep an eye on. Sudden, rapid increases signal a memory hungry process that will soon cause VM swapping to occur.
This data is collected from
/proc/meminfo on Linux systems.