Clear Cached Memory on Ubuntu

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

2012-03-17 08:27:58

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What Others Think

Funny trick, but yes never use it on any prod machine. There can be so much set in cache between the two commands, that it looks like naked free fall.
makidoko · 500 weeks and 3 days ago
drop_caches doesn't drop READ/WRITE-requests. only cached information. SYNC as well as echoing into DROP_CACHES is non-destructive
Syntaxerror · 359 weeks and 5 days ago
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luciham20 · 2 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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