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I'm wondering if there is any way to specify the size of RAM cache used to store ramfs, tmpfs?

When I look at /proc/, I can't find anything about ramfs size.

Nick
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1 Answers1

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From http://www.kernel.org/doc/Documentation/filesystems/tmpfs.txt:

Further on you can check the actual RAM+swap use of a tmpfs instance with df(1) and du(1).

So simply use df or du (you can also use them for ramfs):

$ df | grep tmpfs
tmpfs             205032      1136    203896   1% /run

so 1136 KB is in use.

$ sudo du -s /run
[sudo] password for jaume: 
1416    /run

so 1416 KB is in use.

Thats's interesting... df and du report different sizes. What is happening here and which one is right?

/run has a subfolder called /run/shm, which is itself a separate tmpfs filesytem (although shown as none):

$ df | grep run
tmpfs             205032      1136    203896   1% /run
none                5120         0      5120   0% /run/lock
none              512572       280    512292   1% /run/shm

Adding both amounts you get the size reported by du:

$ expr 1136 + 280
1416

So the whole story is that 2 tmpfs filesystems use 1416 KB.

(Here's another reason why du and df outputs may differ.)

jaume
  • 5,657