Primary System Swap Area Not utilised

[Senthil_15]

The primary swap area of the system is not being utilised and only the Physical Memory is being used.
Please suggest

[Jean-Luc Oudart]

you are using pseudo-swap.

could you post : "swapinfo -tam"

Regards
Jean-Luc

[A. Clay Stephenson]

This is good news. I suspect that you have swapmem_on=1 (pseudoswap enabled) so that what you see in the swapinfo display as "Memory" make you think that memory is being used for swap space. It isn't used like that at all; it's simply a means of kernel arithmatic that let's the system thing it has more swap space than it actually has.

[Senthil_15]

Hi,

You mean to say that I have to turn swapmem_on to "0" to see my swapping that is actually happening on the system.

Please find swapinfo output


/usr/sbin/swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 4096 0 4096 0% 0 - 1 /dev/vg00/lvol2
dev 25600 0 25600 0% 0 - 1 /dev/vgswap/lvolswap
reserve - 4096 -4096
memory 12624 8983 3641 71%
total 42320 13079 29241 31% - 0 -

[A. Clay Stephenson]

No. You aren't actually swapping at all. With swapmem_on=1 then 75% of your physical memory is counted as swap space -- eventhough it's never really used for that. Witout pseudoswap, all process memory reservation must be done using actual (device, filesystem) swap space eventhough you might not ever actually have to swap.

Suppose that you have 16GB of memory and 4GB of device swap. Without pseudoswap, you could run no more than 4GB's of processes eventhough you have 12GB of memory free because only 4GB of space could be reserved. With pseudoswap your could run 16GB of processes (12GB pseudoswap + 4GB device swap). Pseudoswap is intended for those machines that have more physical memory than actual swap space but it is never actually used as swap space.

[Ted Buis]

You have a good environment, you never want to actually page out ("swap"), so count yourself lucky. This means your system is not under memory pressure. If you do swap, however, using pseudowap may not be optimal, but then you may have to add more device swap to equal the total virtual address space of physical device swap area and the memory pages associated with pseudoswap. These pages a just locked in memory so they can't be swapped.