Re: accessing a system with high load

From: Holger.VanKoll@SWISSCOM.COM
Date: Thu Feb 27 2003 - 10:04:14 EST


I dont talk about a certain system.
 
On any system, an application could go wild and eat up all paging. All
applications have memory-leaks, its just a matter of circumstances if
this makes problems.
 
 

        -----Original Message-----
        From: Myers, Drew [mailto:MyersD@GOALAMO.COM]
        Sent: Thursday, February 27, 2003 3:26 PM
        To: aix-l@Princeton.EDU
        Subject: Re: accessing a system with high load
        
        
        I'm guessing the system load is such that you can't tune to
prevent paging?

                -----Original Message-----
                From: Holger.VanKoll@SWISSCOM.COM
[mailto:Holger.VanKoll@SWISSCOM.COM]
                Sent: Thursday, February 27, 2003 9:15 AM
                To: aix-l@Princeton.EDU
                Subject: accessing a system with high load
                
                

                Hello,

                I am thinking about what to do to ensure access to a
system where some application uses that much paging-space that
connections (telnet/ssh/getty) cant be made anymore (fork fails).

                Aix5.1 has the ability (shconf) to do certain things if
certain-priority apps dont get cpu anymore.
                Also, one could start a high-priority ssh-daemon on
bootup.

                Thats fine, but I solves the problem when applications
consume too much cpu. That doesnt help if they consume too much
paging-space.

                As far as I see even ulimit/wlm has no way to solve this
problem.

                I could try to start sshd with plock(); but that would
only get sshd up running... any command started from there still fails
(fork - not enough memory available now).

                So far, I see no other possibility than to increase
paging-space and set high values for npswarn and npskill (vmtune).
                The only disadvantage I currently see is more disk-usage
for paging-space.

                What do you think / what do you do to ensure access to a
high-paging system?

                Regards,

                Holger



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