SUMMARY: task table full

From: Jens Pohl <jpohl_at_physnet.uni-hamburg.de>
Date: Mon, 13 Mar 2000 16:28:57 +0100

Hi,

My question was:

What does the message "vmunix: task table is full" in the the kernel-
and message-log mean?
We have a Tru64-Unix 4.0F mashine, which runs whole the time without any

problems. But after this several 100 of this message within 15 minutes
it crashed down.

What is the reason and what can we do to prevent this?


Thanks for the answers.
Here is the summary:

Increase the following value and reboot

# sysconfig -q proc
proc:
max-proc-per-user = 256

max-threads-per-user = 256

per-proc-stack-size = 2097152
max-per-proc-stack-size = 33554432
per-proc-data-size = 134217728

--------------------------------------------

As it says: your task table filled up. You are not able to create new
processes and things go down hill rapidly from there.

The solution is to increase kernel parameters. In particular, look at:

proc: max-procs-per-user
proc: max-threads-per-user
proc: maxusers
proc: task-max
proc: thread-max

I find dxkerneltuner the safest way to change these parameters. It can
be
done on the command line with sysconfigdb and manually by editing
/etc/sysconfigtab as well.

-----------------------------------------------------

I'd recommend runnig sys_check (should be in /usr/sbin) on
your system. It will make some recommendations on system
tuning (it will beat the heck out of the machine for the
duration of the run, but it is worth it).

Your error messages suggest that you need to tune the
vm subsystm (sysconfig -q vm).

vm:
        vm-mapentries=16384
        vm-ubcseqpercent=20
        vm-ubcseqstartpercent=40
        vm-vpagemax=131072
        vm-page-free-target=256

Are the additions that I made to /etc/sysconfigtab (be careful
making changes, you can't just cut 'n paste ... those need to
be tabs). dxkerneltune will do the right thing. In most cases
you'll need to reboot.

Also look at the proc subsystem.

----------------------------------------------



--
Jens Pohl
--------------------------------------------------------
Jens Pohl                Tel.: +49 (0)40 42838-2404
PHYSnet-Rechenzentrum    Fax.: +49 (0)40 42838-2503
Universitaet Hamburg     eMail: jpohl_at_physnet.uni-hamburg.de
Jungiusstrasse 9         URL: www.physnet.uni-hamburg.de
D-20355 Hamburg
Received on Mon Mar 13 2000 - 15:50:51 NZDT

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