topic Re: Change kernel parameter on RAC enviroment in Operating System - HP-UX

Change kernel parameter on RAC enviroment

ATHANASOPOULOS PANAGIOT — Mon, 11 Apr 2005 03:58:50 GMT

I have a RAC with 2 HP-UX rp7410 servers.
In the first one (node1) I have installed the oms.
I must change the max_thread_proc from 64 to 256. When I change this parameter on the node1 the kernel don't boot the system.
Must I change the same kernel param on the node2?
Which proccess I must follow?

Re: Change kernel parameter on RAC enviroment

Mohanasundaram_1 — Mon, 11 Apr 2005 05:18:59 GMT

Hi AP,

I think I have seen this problem earlier. If you are using the oracle document for the kernel modifications, then there is a problem in one of it.

Though I do not remember if it is max_thread_proc. But once you modify this, then another dependant value becomes a very large value, that the kernel fails to boot.

So check all the dependant parameters when you modify them and confirm which is increasing to an unusual level.

If you can wait for few hours, I may try to find the values myself.

With regards,
Mohan.

Re: Change kernel parameter on RAC enviroment

ATHANASOPOULOS PANAGIOT — Mon, 11 Apr 2005 05:21:14 GMT

ok, I will search.
But if you find smt please let me know.

Re: Change kernel parameter on RAC enviroment

Mohanasundaram_1 — Mon, 11 Apr 2005 05:39:18 GMT

Hi AP,

Do me a favour by sending the oracle document with the recommended kernel values.

My memory says that the offending value is either ncsize or vx_ncsize. Monitor these 2 values when you modify the kernel parameters.

I hope you have eliminated the chances for a memory constraint in this case. What is the memory in your system BTW.

With regards,
Mohan.

Re: Change kernel parameter on RAC enviroment

ATHANASOPOULOS PANAGIOT — Mon, 11 Apr 2005 05:58:00 GMT

My memory is up to 8GB.
I find this solution in the metalink.oracle.com:

Subject: Oracle Management Server crashes frequently

* fact: HP 9000 Series HP-UX
* fact: Oracle Management Server 2.2
* fact: Oracle Management Server 9
* symptom: Oracle Management Server crashes frequently
* symptom: oms.log shows errors
* symptom: VDD: caught exception java.lang.OutOfMemoryError: can't create another thread
* symptom: Management Server Restarts When Multiple Events Are Registered / Deregistered
* cause: The value of the kernel parameter MAX_THREAD_PROC is too low. By default the value of this parameter on HP is 64. The release notes for Oracle 9i on HP state that this parameter should be set at least to 1024

fix:

1. Run /etc/sysdef or /usr/sbin/kmtune to check the value of MAX_THREAD_PROC

2. Set the UNIX Kernel parameter MAX_THREAD_PROC to 1024 or higher in
/stand/system using HP Tool SAM

Re: Change kernel parameter on RAC enviroment

Mohanasundaram_1 — Mon, 11 Apr 2005 06:02:34 GMT

Hi AP,

Thats good. Is that solution working for you? Has it solved your problem?

Just post the details before closing this thread.

With regards,
Mohan.

Re: Change kernel parameter on RAC enviroment

ATHANASOPOULOS PANAGIOT — Mon, 11 Apr 2005 06:15:43 GMT

I only want to know which is the right procedure that I must follow.
I should go the node1 on single user mode and change the param and then on the other node or it doesn't matter if one node has diferent param from the other one?

Re: Change kernel parameter on RAC enviroment

Thayanidhi — Mon, 11 Apr 2005 06:37:00 GMT

It's not a application patch you afraid to do in one node without doing the other one.
Kernel parameter could be changed one by one, as long as it doesn't affect the running Oracle.
Stop one node and change the parameter and restart, start the node (package), then repeat the same in the other node.

If you can plan a outage better take outage and do both at same time.

TT