Operating System - Tru64 Unix
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Unable to fork process

Ricardo Ballesteros
Occasional Visitor

Unable to fork process

Hi, we are installing SAP R/3 on a Tru64 5.1B with oracle database and when the installation program starts with the database creation the error hapens. Wich is the cause of the error?

Additionally in a SAP documentation SAP recomends some tru64 kernel parameters but because this server supports another applications databases we have a doubt about modifing some parameters, those are:
ubc_minpercent = 5
ubc_borrowpercent = 9
ubc_maxpercent = 10
vm_ubcseqstartpercent = 50

We need to know the impact that those parameters do on the entire oracle database server.

Additionally I attach you the note from SAP about the tru64 parameters.
Michael Schulte zur Sur
Honored Contributor

Re: Unable to fork process


should there be resource problems that lead to the problems with forking tru64 will log it in /var/adm/messages. Have a look there and tell us what you find.


Hein van den Heuvel
Honored Contributor

Re: Unable to fork process

The parameters you mention appear correct and should have no impact on the install even if they were wrong.

The parameters document is slightly dated. It is a moving target. For eample: V5.1B BL24 and later require vm:new_wire_method=1.
For earlier versions you must still use vm:new_wire_method=0.
You may want to check with Oracle, more so than SAP, as to configuration requirement.

Also, I woudl recommend to escape from the SAP install, install Oracle 'manually', and restart the SAP install. That'll give you more control, clearer error messages... if any.

As for the real problem... my guess? It is not going to be a fork problem, but like a bad Java image/directory/environment variable, which is possibly only an issue with install, not with production usage.

Finally... you are probably not installing out of the blue. Did it work before? Don't you have support? THere is excellent support through SAP which will use HP resources in Walldorf if needed.


Han Pilmeyer
Esteemed Contributor

Re: Unable to fork process

Don't think your problems originate from those UBC settings, but you should definitely not use the UBC settings as suggested by the document you attached. I would suggest setting ubc_maxpercent to 90 and leave all others at their system default value.
Joerg Schulenburg
Frequent Advisor

Re: Unable to fork process

I postulate following things:

sysconfig -q vm vm_swap_eager # shows 1

I assume also, that swap is not very big (swapon -s).

If you have an application, that consumes
lot of memory and that application want to fork, it needs two times of its own memory to
double the process. If you dont have enough
swapspace free, fork will fail.

Above statement is just a assumption. I can not proove it, but may be it helps.
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