physical memory % free

This is the percent of free (available) real memory space on the specified hosts.

Physical memory is for working processes. Linux puts idle processes onto the SWAP memory. This means you can have a virtual memory that is almost full, and still have available space in the physical memory.

Both Physical memory free and Physical memory % free are divided into three sections:

  • Physical memory (hardware or hard-drive partition)
  • Buffer
  • Cache

    Cache is used when processes load documents, and can be freed if additional memory is required. You also can have a virtual memory that is almost fully used. The available space can be increased by flushing the cache.