disk cache chews up memory and won't let go

TomaCzar · 03-07-2004, 12:49 AM

I've been trying to get my arms around Slackware Linux for the last few months and I'm damn close, but just not hitting the mark. I've tried google and the forums and newsgroups, but this one's eluding me. On all of my machines, regardless of kernel or configuration, for some reason all of my memory gets eaten up by disk cache. Even the box with 2gigs of RAM eventually all gets used and never released. I don't know WHERE to begin to start looking, any help would be greatly appreciated. Oh yes, while I'm sure there's some file associated but I don't know what it is, so if there's a .conf you need, just say the words.

davidsrsb · 03-07-2004, 04:54 AM

The cache grows to use all available ram. The when you need more ram for processes just suficient cache is released. Linux boxes don't like having unused ram.

TomaCzar · 03-07-2004, 09:06 AM

Holy hand grenades. For two months I've been trying off and on to fix this problem, only to find out that that's the way things ought to be. No wonder I couldn't find any help on the subject. Thanks so very much for letting me know.

Phathead · 03-07-2004, 01:51 PM

If you type "free" at the console, you should see something like this:

Code:

             total       used       free     shared    buffers     cached
Mem:        514968     509792       5176          0      22152     336496
-/+ buffers/cache:     151144     363824
Swap:       979956          0     979956

You can see how much memory is actually free less disk cache.

Alternatively, you can use "free -m" to get the figures in megabytes:

Code:

             total       used       free     shared    buffers     cached
Mem:           502        497          5          0         21        328
-/+ buffers/cache:        147        355
Swap:          956          0        956

As you can see, it looks like almost all my memory is used up, but looking at the line that has "-/+ buffers/cache:", I'm only using 147 MB.