>The UNIX osf system persistantly shows following error message:
>
>Unable to obtain requested swap space
>swap space below 10 percent free

You don't have enough page/swap space. You can use the swapon(8) command to add more raw disk partitions as page/swap space devices.

Or, as another reader suggested, switch to deferred page/swap reserveration mode. Ordinary, page/swap space is reserved for every page of (anon.) virtual memory created. This ensures that if the page needs to be written to the page/swap device, there will be space for it. The deferred mode doesn't do the reservation.

The advantage is that it allows the limit on virtual memory to be appoximately the sum of page/swap space and available memory. The disadvantage is that if you run out (which you're doing now), the kernel will resolve any deadlock situations by killing apparently idle processes. If you are in an environment where you can accurately estimate virtual memory and control it, this mode is fine. If you're in an environment where you can't, deferred mode can be used as the target of a denial of service attack.

Personally, I'd go with the "add more page/swap space".

Alan Rollow

mkfile 100M /home/swap_100meg
swap -a /home/swap_100meg
swap -l