Understanding free output in Linux
If you are managing Linux machines daily like me, its important to understnad the output of free command, which shows the free system memory.
[root@localhost vagrant]# free
total used free shared buff/cache available
Mem: 5824332 2292284 1155732 132980 2376316 3087844
Swap: 839676 18172 821504
[root@localhost vagrant]#free -g is much more helpful instead
[root@localhost vagrant]# free -g
total used free shared buff/cache available
Mem: 5 2 1 0 2 2
Swap: 0 0 0
[root@localhost vagrant]#Some flavours of linux might output in this format:
total used free shared buffers cached
Mem: 62 46 16 0 0 10
-/+ buffers/cache: 35 27
Swap: 0 0 0
------------------------------ total - Your total, physical (assuming no virtualization) memory
- used - How much of that is currently used (by anything)
- free - How much of that is completely free (not used at all)
- shared - (never anything there, ignore that column)
- buffers - Memory used by kernel buffers
- cached - Memory used for cache
Essentially, the figures which we should be focussing on is -/+ buffers/cache which excludes the used buffer.