Paging space size

[Janghyegyung]

My Aix4.3.3 has met this error, when the whole system was actually hang up..
"cannot fork, no swap space"

I think this came from my small paging space. Right?

What is the recommended paging space size for my AIX?

Thank you.

 

[farhsyed]

Hi,
you are right. Swap space needs to be increased. there is a simple formula in AIX documentation but usual recommendations are to have swap space double the size of your actual RAM in your system. i.e. if you have 512 mb RAM, the swap could be 1024 mb(1 gb).
farhsyed

 

[vickersdc]

It's not quite a simple as 2x RAM(MB) - check out my FAQ on "Understanding How AIX Manages Memory / Page Space" where you'll find the correct formula to use.

Hope it helps.
Dave V.

 

[farhsyed]

Hi,

Following is taken from one of IBM Red Books:
"
7.1.1.2 Sizes of Paging Spaces

The general recommendation is that the sum of the sizes of the paging spaces should be equal to at least twice the size of the real memory of the machine up to a memory size of 256 MB (512 MB of paging space).
For memories larger than 256 MB, the following rule is recommended:

Total paging space = 512 MB + (memory size - 256 MB) * 1.25"

Thanks

farhsyed