Active - The total amount of buffer or page cache memory, in kilobytes, that is in active use.

SwapCached - The amount of swap, in kilobytes, used as cache memory.

Cached - The amount of physical RAM, in kilobytes, used as cache memory.

Buffers - The amount of physical RAM, in kilobytes, used for file buffers.

MemFree - The amount of physical RAM, in kilobytes, left unused by the system.

MemTotal - Total amount of physical RAM, in kilobytes.

But by looking directly at /proc/meminfo, more details are revealed: In fact, the output of the free command is similar in appearance to the contents and structure of /proc/meminfo. Much of the information here is used by the free, top, and ps commands. The following sample /proc/meminfo virtual file is from a system with 256 MB of RAM and 512 MB of swap space: MemTotal: 255908 kB It is one of the more commonly used files in the /proc directory, as it reports a large amount of valuable information about the systems' RAM usage.

It provides the current memory usage details rather than old stored values. This file contains all the data about the memory usage. The sar command will show only CPU monitoring activity if any flag is not specified by the user.

Any user can collect information about system performance using system activities flags. Linux system monitoring and analyzing aids in understanding system resource usage, which can help to improve system performance to handle more requests.īy default sar command displays results on the output screen in addition results can also be stored in the file specified by the -o filename option. The sar command can be used to monitor Linux system’s resources like CPU usage, memory utilization, I/O devices consumption, network monitoring, Disk usage, process and thread allocation, battery performance, plug and play devices, processor performance, file system and more.

Sar command to check cpu utilization