Excessive swap file

kappauk · 07-07-2010, 11:17 AM

Hi just a quick question...

We have just been looking at a swap file on one of our Linux boxes and have noticed it's at 23gb which seems pretty big.
I was wondering is there a way we can find out

A: What it's original size was (so we can see how much it's grown)
B: What's in the file at the moment.

Cheers

smoker · 07-07-2010, 12:15 PM

I didn't think there was a swap "file" in linux. There is a swap partition but you don't access it from a filesystem. You can run top to see details about it's size and usage, but it is not a dynamically resized item.

Maybe you are looking at something in /tmp ?

michaelk · 07-07-2010, 12:53 PM

Yes, you can have swap file(s) in addition to partition(s). AFAIK and as already stated they are not dynamic. swap is not mountable nor is it a real filesystem but it maybe possible to examine its contents with utilities like testdisk and photorec. Without reference to hardware and what type of applications you run it is difficult to say how much swap is really required.

BTW tmpfs is dynamic and can shrink and grow as required.

syg00 · 07-07-2010, 05:51 PM

A: As stated above, it won't have "grown" - that was the size it was initially allocated (file or partition, same applies).
B: "swapon -s" will give you the status of any/all swap extents currently in use.

Unless you are using RHEL, that size is just a waste of disk space, as the system won't use it all (RH have a patch to use bigger).