Swap is not being used in Redhat Linux 6.1 & 6.2 Systems...

[Gopinath_1]

Hi,

I have a problem in many of my office servers running on redhat linux 6.1.Thing is that, most of the Linux system is not using the Swap space at all even though there is plenty of swap space is configured.

Whenever, i load a X application, it simply sits in the Pphysical memory and not even touching the swap space.

When i use 'top' command it shows my swap space usage is 0 always.

I would really appreciate the responses..

Gopinath

[RikTytgat]

Hi,

Your system only uses swap if the physical memory is not big enough to contain everything you run.

On my RH6.2 system, the swap utilisation is very low (1600KB out of 291000KB), but this is because my physical memory is quite large (192MB).

When I start a lot of X applications, my swap usage starts to increase.

So, I suppose you have enough physical memory and there should be no reason to worry.

Hope this helps,
Rik

[Tim Malnati]

Rik is correct on this one. Not using swap space is a good thing. Any data that has pushed to swap will require a lot more time to actually access if and when the system needs it for processing (disk access is much slower than memory access). Most of the unix varients do the same thing. I think that maybe you are comparing this to the pagefile in Windows? It's common for both NT an 9.x to throw stuff out there immediately. This is just another reason why the MS OS's are not as efficient.

[Philip Chan_1]

Don't worry about swap space not being used, this is actually a good sign that your system will run at full speed without doing any paging!!!

Despite of what I said above, make sure your swap space are indeed configured properly, try starting several copies of memory eager program like StarOffice or Sybase then do a "free", "vmstat" or "swapinfo" to check.

By the way, how much memory you got for your machine. I guess 128MB is well enough to avoid using virtual memory in most cases.

Rgds,
Philip