nkthread

[khilari]

Hi people, i was was cmruncl to get my two node cluster back up, when it gave me the error that nkthread size is full. It is 499 and 499 used. Now there is a formula which i really dont want to mess with. So, how should i go about changing or increasing the value..
And secondly, i thought nkthread was java related so why is it interfering with re forming the cluster.
Thanks

[Prashant Zanwar_4]

This has happened at my end also.. and you have to bump system parameters for this to be avoided. You need to adjust your kernel values.. Check below paper and do it accordingly..
If system is new, you need to change it mostly..
Check what type things have changed on system..

Hope it helps
Prashant

[Steven E. Protter]

Shalom,

Take out the formula.

As a matter of course, many admins take out these formulas which limit flexibility and often serve no purpose other than to drive admins up a wall.

I don't think nkthread is java releated though if its not high enough java may not run right.

SEP

[John Bigg · Accepted solution]

nkthread is only java related in that java can take a lot of threads so typically needs to be increased in java environments. Any system which uses a lot of kernel threads may need to have this parameter increased. Note that every process takes at least 1 thread and processes such as java and Serviceguard's cmcld can take more.

If you are unconfortable removing the formula you could consider modifying it to add a larger static value to handle the extra threads taken by multi threaded processes.

i.e. I think the default fomrula is:

((nproc*2)+16)

you could change this to:

((nproc*2)+256)

so it will still be automatically scaled if nproc is increased but will have an additional 240 threads on top of the old value. Or maybe change the multiplier if you think this would be more appropriate for your environment.