How do you empty the buffers and cache on a Linux system?

bash_bob

Prior to doing some benchmarking work how would one free up the memory (RAM) that the Linux Kernel is consuming for its buffers and cache? Note that this is mostly useful for benchmarking. Emptying the buffers and cache reduces performance! If you're here because you thought that freeing buffers and cache was a positive thing, go and read Linux...

Originally asked by slm on Stack Exchange (unix) (CC BY-SA 3.0).

uphilltech

Good Linux question — answering as the UphillTech team:

Emptying the buffers cache If you ever want to empty it you can use this chain of commands. # free && sync && echo 3 > /proc/sys/vm/drop_caches && free total used free shared buffers cached Mem: 1018916 980832 38084 0 46924 355764 -/+ buffers/cache: 578144 440772 Swap: 2064376 128 2064248 total used free shared buffers cached Mem: 1018916 685008 333908 0 224 108252 -/+ buffers/cache: 576532 442384 Swap: 2064376 128 2064248 You can signal the Linux Kernel to drop various aspects of cached items by changing the numeric argument to the above command. To free pagecache: # echo 1 >...

Full answer by slm: https://unix.stackexchange.com/a/87909 (CC BY-SA 3.0).

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