kernel

[Tvs]

hai..

i reconfigured the kernel by system_prep , and mk_kernel.

i just want to check whether the system will properly boot with new kernel before shuting down the system

whether it is possible..?

[Patrick Wallek]

I don't think that is possible. When you move the new kernel into place, make sure you move the old one to vmunix.prev and the old system file to system.prev. That way you can boot from the old kernel if the new one doesn't work.

[rveri]

Hi Sunil ,

You need to use the command # kmupdate ( it will move the newly build kernel to vmunix and current kernel to vmunix.prev to get effect in next reboot.) Also need to copy the previous system file as system.prev

And in next boot if it doesnot boot , need to boot from vmunix.prev .

Cheers,
R.Veri.

[A. Clay Stephenson]

Actually the steps to follow are (at least for 11.x):

kmtune -s dbc_max_pct=5
(repeat as often as necessary to set the desired tunables)

mk_kernel

kmupdate

[baiju_3]

with 11.x

easy to use sam to update the kernel , other wise you may have to do kmtune etc.

Compare the size of your existing kernel and the one you created .


Also keep a copy of the old kernel before moving the new kernel inplace .

In my knowledge there is no command as such you can use to verify the Kernel , whether it is bootable or not .


Thanks,
BL.

[Bill Hassell]

If you manually change parameters with the command line parameters, it is certainly possible to create an unusable kernel. It may boot but crash due to one or more kernel parameters that are far too large or small. You need to save the current kernel so you can boot from it in case the new kernel fails.

All of this is done automatically for you by SAM with the added benefit that virtually all the parameters have extensive documentation (Help on Context) and most parameters are checked for valid limits as well as cross-checking with other parameters.

[Simon Hargrave]

I'll second the motion for using SAM. Whilst using kmtune etc is fine, SAM has built-in features for ensuring you don't do silly things (like setting nproc < maxuprc).

If you have a standard set of modifications to apply to all boxes that you've already tested with SAM, then fine use kmtune, but in nearly all other cases I'd trust SAM on this one.