On 4 Aug 2005, at 12:01, Ole Tange wrote:
> server$ free
> total used free shared buffers
> cached
> Mem: 3879664 3135160 744504 0 139772
> 1353624
> -/+ buffers/cache: 1641764 2237900
> Swap: 1023992 357120 666872
>> On this server you will notice that there is 1.3 GB cache, 744 MB free
> and
> 357 MB swapped out. This is caused by a large program just endning
> freeing
> around 700 MB. In time the disk cache will grab the 700 MB free if not
> a
> program will need it. The swap is caused by idle memory that is
> swapped to
> disk if more disk cache is needed.
I don't think that's quite right. When you think about it, it doesn't
make sense. Free memory is used for disk cache because that's a good
use of memory, avoiding possible future disk I/O. Swapping idle memory
to disk (causing I/O) to avoid possible future disk I/O doesn't sound
like a good investment. The use of swap above was caused by the 700 MB
program which just stopped - when the system has used swap, it doesn't
purge the used pages - the only way to do that IME is to run swapoff.
Niall
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