[19:06] <vorathiel21> Hi people, i wanna   put   /home/user/.cache  and   /tmp  directories  in  /run/shm   to increase performance and   clean temp files on every reboot.  Can i do this with symlinks  ??
[19:29] <cmaloney> vorathiel21: I'd recommend using tmpfs for /tmp
[19:30] <cmaloney> https://askubuntu.com/a/173294/1614
[19:31] <cmaloney> as far as cache is concerned unless there's a reason not to write .cache I'd leave it alone
[19:31] <cmaloney> reason being:
[19:31] <cmaloney> There's a lot of things in there that will take longer to re-create
[19:31] <cmaloney> eg: thumbnails and the like
[19:32] <cmaloney> so you'll slow your machine down if you constantly re-create cache
[19:37] <vorathiel21> thanx for your answer.  i've already try  tmpfs  .  it worked fine . The thing is today  i discover  this /run/shm  directory
[19:37] <cmaloney> It's the same thing
[19:37] <cmaloney> If you cd to /run and type `df .` you'll see that it's using tmpfs
[19:39] <cmaloney> https://askubuntu.com/questions/169495/what-are-run-lock-and-run-shm-used-for
[19:42] <vorathiel21> don't you think if i put  those  directories under  /run/shm  , them will share the space ??   i think it's a waste of ram to declare  separated  tmpfs in fstab for  /tmp  and  .cache  ... if there is already a ramdrive available on  /run/shm
[19:43] <vorathiel21> am i wrong ??
[19:43] <cmaloney> I think you're misunderstanding how Linux allocates RAM
[19:43] <vorathiel21> it can be possible
[19:44] <cmaloney> tmpfs is not cordoned off the way you might think it would be for a physical disk
[19:44] <cmaloney> eg: /run/shm doesn't have half of your memory allocated
[19:45] <cmaloney> It's showing the maximum that it will allocate
[19:45] <cmaloney> What is allocated is what you see when you run df
[19:46] <cmaloney> Linux tries to keep as much in an internal cache as possible for performance
[19:46] <cmaloney> and will free up those pages as memory pressures become larger
[19:46] <cmaloney> That's why if you run `free` you'll notice that there's precious little memory left
[19:47] <cmaloney> that's Linux trying to ensure that it goes to disk as few times as it can
[19:47] <cmaloney> most of the time it'll read things from cache
[19:48] <vorathiel21> hmmm
[19:49] <cmaloney> here's an easy test
[19:49] <cmaloney> as root:
[19:49] <cmaloney> sync; echo 1 > /proc/sys/vm/drop_caches
[19:49] <cmaloney> that will clear out the cache
[19:49] <cmaloney> then run (as a normal user) `watch free`
[19:49] <cmaloney> and use your machine
[19:49] <cmaloney> You'll notice it start to fill up the cache again
[19:50] <vorathiel21> i understand.  So... linux already is doing what am trying to do
[19:51] <cmaloney> Exactly
[19:51] <cmaloney> changing /tmp to tmpfs is still a decent idea
[19:51] <cmaloney> I do it on all of my machines
[19:52] <cmaloney> but going much beyond that isn't going to give you what you think it will
[19:55] <vorathiel21> thank you for enlightening me on this
[19:56] <cmaloney> no problem. glad I could help
[19:56] <vorathiel21> c ya
[19:56] <cmaloney> ttyl