AIX: PID 0 Process

UNIX AIX
1

Hi All,

I searched other threads and could not find any relevant post about this.

I searched for process 0 in SUN OS and could find the sched/swapper process listed.

root     0     0  0   Apr 25 ?        0:06 sched

but i couldnt not find the swapper process (PID 0) in AIX. Is that process not required in AIX? What job does SWAPPER process do apart from starting the init service?

In AIX:

$ ps -ef|sort -nk2 |head
     UID      PID     PPID   C    STIME    TTY  TIME CMD
    root        1        0   0   Apr 01      - 24:23 /etc/init

Regards...

Next time use CODE-tags when posting code, data or logs for better readability and to keep formatting/indention etc., ty.

2

Solaris uses swap. AIX utilizes paging space. /usr/sbin/syncd does the appropriate task in AIX.

Swapper/syncd do not start the init service. They are responsible for cleaning/recovering virtual memory.

Here is a link that explains why paging is better than swap: FoRK Archive: paging v. swapping

3

Hi,

Hi Quintet,

ps -ef would not show you the process anyway since its a kernel- not a userprocess - but ps -k shows you the kernel processes.

At least on my box pid0 is swapper, pid1 is init and pid3 is sched :slight_smile:

Kind regards
zxmaus

4

Hi Guys,

Thanks for your answers. It really helped. And yes ps -k did list the swapper process.

Is there any command to know whether the system supports SWAP or PAGING?

Regards..

5

Hi,

what do you mean with 'if the system supports paging'? We tend to try avoid paging as good as we can :slight_smile:

AIX uses paging space as virtual memory ... usually hdisk6 but you can define further paging areas.

lsps -a shows you details about your paging areas, eg number, location, size, usage and anything else.

AIX cannot run without a paging area - it will not start at all, so you need to have at least a small one small paging area in your rootvg - further paging areas can be defined as you like.

You can tune the virtual memory manager how to use this paging area - eg to page out only noncomputational memory in case of need but whenever you are drastically exhaust the amount of real memory in your box, the system will use the paging area for everything - fighting for survival. And once the paging space is full, the box will either start forking and killing processes randomly - or restart itself.

Hope that helps
kind regards
zxmaus