maxdsiz and recompiling the kernel 1

[daveleo]

hi

I own and operate an HP-ux11.0 machine, but am not a unix systems wiz, and don't have direct access to an expert..... and I have a problem running a new piece of software that is correctly installed on this machine.

The error message when trying to run the program was:
"Pid 4627 receieved a SIGSEGV for stack growth failure. Possible causes: insufficient memory or swap space, or stack size exceeded maxssiz. Memory fault (core dump)."

The computer has 3Gb of memory (about 2.3Gb are free).

The help desk (where I got the software) offered this response:

The HP-UX kernel has a default stack size of 8MB(?) per process.
You need to extend maxssiz and recompile the kernel (and reboot).
You can use SAM to do this.
(While at it, check out the maxdsiz parameter for the maximum amount
of data a program can use. It depends on your applications, if the
default of 64MB is enough or not.)

Here's what we use on our systems:

* Max Data Segment Size (bytes)
* our systems (3*1024*1024*1024)
maxdsiz 0XC0000000
* our systems - Recommended by SAM template (16*1024*1024*1024)
maxdsiz_64bit 0X400000000

* Max Stack Segment Size (bytes)
* our systems (256*1024*1024)
maxssiz 0X10000000
* our systems (1024*1024*1024)
maxssiz_64bit 0X40000000

* Max Text Segment Size (bytes)
* our systems (1024*1024*1024)
maxtsiz 0X40000000
* our systems - Recommended by SAM template (4*1024*1024*1024)
maxtsiz_64bit 0X100000000

..................................................

I have used SAM for some minor tweaks before.
The part that has me really anxious is "recompile the kernel".
This sounds like a very serious action and open to some very bad consequences.
I will not even attempt this until I've read much more.

My question is ..... (1) is recompiling the kernel necessary to change maxdsiz, etc and (2) is recompiling the kernel a step by step process in SAM.

Thanks for any guidance.

daveleo

 

[iribach]

i feel your 'help desk guys' (as usual) have no idea,
thery are grabing at a cheep answer.
i don't know HP-UX, but at 99% you sure don't have to
recompile the kernel.
the problem is what else, sorry cannot help you.

 

[RanganathRamachandra]

on hpux, maxssiz happens to be one of those kernel parameters which need a kernel rebuild in order that changes in their values take effect. so what your helpdesk is suggesting is hp's recommended way of doing it.

 

[daveleo]

to close out this topic.....

i did learn enough about configurable kernel parameters to go ahead and make the changes, and yes, i had to recompile the kernel, but in SAM it was a one-click operation (though i did sweat a lot watching it reboot).

so it was one of those 4-hours-and-ten-minute jobs.....4 hours to read and learn and 10 minutes to execute.

thanks for the input.

daveleo