changing kernel values w/o immediately rebooting

[Doug_3]

Can someone tell me if it is possible (and recommended) to change kernel parameters w/o forcing an immediate re-boot?

Thanks in advance,
Doug

[Sundar_7 · Accepted solution]

Hi Doug,

In 11i v1, we have something called Dynamically Tunable Kernel Parameters (DTKP). There are set of kernel parameters which you can tune without having to reboot the server.

# kmtune | grep " Y"

this should give u the list of parameters that you can tune online.

I understand in 11i v 2 and above, there comes parameters which get automatically tuned :-)

-- Sundar

[Pete Randall]

Doug,

It's possible, though I'm not sure about recommended. I've used SAM in the past, rebuilt the kernel, then left SAM sitting at the reboot prompt until I was ready. I suppose there's some small risk with losing the session and thus the prompt, but I would think you could just issue the reboot manually when you were ready anyway.

I can't really think of any other downside. It's not like when you're applying patches and you have filesets in an inconsistent state with your running kernel. I'll be interested to see if anyone comes up with cautions.


Pete

[Patrick Wallek]

I did this just this past weekend.

I went through SAM, made changes, told it to process a new kernel. When it asked about moving the kernel into place and rebooting the system, I told it no I'll wait until later (whatever the appropriate menu choice is). SAM then informed me that I would have to run kmupdate and move /stand/build/system.SAM to /stand/system and reboot the server for the changes to take effect. I did that later that night, prior to a regularly scheduled reboot (Please don't ask!!!!). Everything seemed to work fine.

If you ware going to make changes and not reboot immediately, I'd recommend this route.

[Pete Randall]

I like Patrick's "Nancy Reagan approach": just say no!

;^)

[PVR]

Only dynamically tunable kernel parameters can be changed w/o reboot. HP offers a very few such parameters. So most of the times you have to build a new kernel and reboot