User process number limit? cannot fork: too many processes

[Brian_71]

Is there a limit on how many processes a user can create? I have the num of procs let to like 5000 and there are only 350 running on the machine, but I am getting this error when trying to su to one particular user who has a lot of procs running. Any ideas?

[James Murtagh · Accepted solution]

The kernel tunable maxuprc determines the maximum number of processes a user can have.

If you are running HPUX 11i, note this is dynamically tuneable.

[Helen French]

Hi Brian:

You may need to increase the kernel parameter - maxuprc. This may solve your issue.

If not, I would check the following:

1) Patch level - update if necessary
2) System usage, processes, resources etc. with Glance (gpm), sar and top
3) check the syslog.log for any more error details.

HTH,
Shiju

[MANOJ SRIVASTAVA]

Hi Brain


do a ps -ef | grep user | wc -l

by default the OS comes with I think 75 that should be incresed . There is no thumb rule to determine what is the safe no as the users can use depending on whether they are databse users etc,So bump it more than 75 I take a safe no as 1000 for a main application user but you can monitor it.


Manoj Srivastava

[T G Manikandan]

Hello,
nproc-total no. of processes on the system
maxuprc-maximum no. of user processes.

I assume the user has exceeded his limit.
check for the maxuprc number on your system.

Also check whether the user has run a progarm where it is going on a loop creating additional processes.

If this is not the case check whether the processes running under the user are all reqd.Also if this is the case then increase the maxuprc value.
A value of 350 for maxuprc is quite enough.


Thanks

[John Carr_2]

Hi Brian

when you increase maxuprc I would do this gradually and cross check to the performance of the server.

I was involved in a situation where a DBA insisted on having maxuprc increased a few years ago and it ground the server to a halt.

If its a production server play safe and do it gradually.

if your o/s level supports kmtune then use command

kmtune -s maxuprc=NNN

else

cd /stand/build
/usr/lbin/sysadm/system_prep -s system
edit system file
mk_kernel -s system
mv /stand/system /stand/system.saved
mv /stand/vmunix /stand/vmunix.saved

mv /stand/build/vmunix_test /stand/vmunix
cd /
etc/shutdown -ry now

cheers
John.

[Bakos György]

Hi eweryone
THX for the fast resolve.
What you must know:
This machine works for 3 years with this configuration, so I think i mustnt change the kernel.
At the moment are there 313 processes, that is normal, it works now fine, but yesterday I have it 4 times rebooted, because It was always: Cannot fork new process.
At the moment I am running on a terminal top to see this process number.
How can I see how many Is the maxnumber of processes?
Thanks again

[Bakos György]

Hi

It says again the he can't fork more process.
I maked a ps and At the beginn I see some vx_inactive_thread

I have attached ps -ef>file , what is the root cause, can somebody help?

[Bakos György]

I tryed to kill this threads, but I can't
(kill -9 51 ....)

[Jeroen Peereboom]

Do not kill the vx processes!!

Instead, you have probably too many assy_tst processes.
I see defunct, dtexec, dtterm, etcetera..

Something must have changed?

A wild guess:
Do you login as assy_tst using CDE? Any changes to it? Do you have 'return to Home session'?

Can you move its .dt directory away?

It's difficult to tell from here...

JP.

[Bakos György]

No nothing changed on the structure...
The nproc is large enough and there is enough memory