Changing swap disk priority on-line

[Ronald Cogen]

Hello,

Is there a way of changing the priority of my LVM swap device without having to reboot? When I tried it using SAM I got a threatening message that the system would first have to reboot to put the device in 'unused', afterwhich I could remove the device and recreate it. All I want to do is change the priority from 0 to 1. Is there a simple way here?

Ron

[T G Manikandan · Accepted solution]

No you can't.
The priority is set when the swap is enabled, so the change requires a reboot.


Thanks

[T G Manikandan]

Another important thing is that the priority of the primary swap cannot be changed.
It is '1'.

Thanks

[G. Vrijhoeven]

Hi Ron,

the priority is default 1. You can change it with # swapon -p /pagingdevice. but i doubt that it can be done online. There is no swapoff commando except rebooting.

Gideon

[Ronald Cogen]

Hello TG,

I wanted secondary swap to have the same priority as primary swap, which would be 1. Perhaps i wasn't paying attention, anyway after I set up the secondary swap I noticed that the priority was 0, which I think would affect the 'load balancing' aspect of the swap mechanismus. Is thins true?

[T G Manikandan]

Ronald you are right!
Interleaving can give better performance for swap.

Good performance can be given by having both swap size as equal and also with the same priority.
Also for good performance avoid using heavily loaded file systems for swap.

Thanks

[BFA6]

Hi Ron,

If your swap areas have the same priority set, then interleaving will happen, which in effect will load balance swapping between the two area.

Regards,

Hilary