clean up memory on linux

sync; echo 3 | sudo tee /proc/sys/vm/drop_caches

where proc filesystem mounted under /proc

Sample Output

By: bandie91

2010-05-23 11:39:35

echo sudo sync tee

8 Alternatives + Submit Alt

Clear filesystem memory cache

Found here: http://ubuntuforums.org/showthread.php?t=589975
This is sample output - yours may be different.
8

sync && echo 3 | sudo tee /proc/sys/vm/drop_caches

mariusbutuc · 2011-10-18 15:22:25 19
clear the cache from memory
This is sample output - yours may be different.
2

sync; echo 3 > /proc/sys/vm/drop_caches

lunarblu · 2009-08-20 17:28:56 7
Clear filesystem memory cache
This is sample output - yours may be different.
2

sysctl -w vm.drop_caches=3

sanidhya_k · 2011-10-18 18:23:38 11
Clear Cached Memory on Ubuntu

Clear Cached Memory on Ubuntu based distributions, and also display memory status. Please do not use this on a production machine unless you really really know what you are doing. Echo 3 is a kinder way of purging the memory, you can also use 'echo 2' or 'echo 1' if #1 You know what you are doing, and #2 refer to number 1 :-)
This is sample output - yours may be different.
0

sudo free && sync && sudo echo 3 | sudo tee /proc/sys/vm/drop_caches

tg0000 · 2021-09-13 16:45:20 568
Clear Cached Memory on Ubuntu

"That's it. Not much to see here. The first command writes any cache data that hasn't been written to the disk out to the disk. The second command tells the kernel to drop what's cached. Not much to it. This invalidates the write cache as well as the read cache, which is why we have the sync command first. Supposedly, it is possible to have some cached write data never make it to disk, so use it with caution, and NEVER do it on a production server. You could ... but why take the risk? As long as you are running a post 2.6.16 kernel,..." Source: http://ubuntuforums.org/showpost.php?p=3621283&postcount=1
This is sample output - yours may be different.
-1

sudo sync && sudo echo 3 | sudo tee /proc/sys/vm/drop_caches

StephenJudge · 2012-03-17 08:27:58 13

What Others Think

Why would you want to do this?

DNSpyder · 725 weeks and 4 days ago

Nice, but what would you use it for other than prettying up /usr/bin/free for management's consumption?

sufoo · 725 weeks and 4 days ago

Buffers and caches in linux only use unused memory, i.e. memory not used by processes. So it's incorrect to think that you are making more memory available for programs by using this, in general. As soon as an application makes a big memory request, the kernel may satisfy that request by "dropping" enough buffers or cache to satisfy the request. Because unused memory is a terrible thing to waste. :-) If you do this, and then want to cache a file's contents (if there is memory available) then simply do cat filename > /dev/null if you run htop you can see the cache fill up as cat reads this file and automatically uses cache if it can.

bwoodacre · 725 weeks and 4 days ago

bwoodacre: its news for me. i had hope it decrease number of pagefaults

bandie91 · 725 weeks and 3 days ago

under what situation i should use this command??

criver · 723 weeks and 5 days ago

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ClaudeVest · 27 weeks and 4 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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