Kernel parameter change

[Kapil Jha]

Gurus,
I have a general doubt not related to only Tru64 but as a general unix.
How we would come to know that changing a kernel parameter needs a kernel rebuild or would be effective after a reboot just adding it to sysconfigtab file.
using
sysconfig -r

BR,
Kapil

[Rob Leadbeater]

Hi Kapil,

You'll normally find such information in the relevant man page for the paramter you're changing.

For example in the man page for sys_attrs_vm

http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/V51B_HTML/MAN/MAN5/0053____.HTM

You'll see that those attributes marked with an asterisk can be changed with the system running.

Hope this helps,

Regards,

Rob

[Vladimir Fabecic]

Hello Kapil
It is not a simple question.
In general, it depends on kernel and OS architecture.
In all modern unix-es changing a kernel parameter does not need kernel rebuild, but may need OS reboot.
If installing new hardware or or some new core software component, it is very likely that you need kernel rebuild because you need to have some new modules in kernel.
Also, patching requires kernel rebuild because of modules and library changes.
For example, old SCO unix needed kernel rebuild even after changing IP address.
As said by Rob, man pages will give you answer for particular unix.

[Rob Leadbeater]

Hi,

Vladimir said:

> old SCO unix needed kernel rebuild even after changing IP address

From what I've seen of it, SCO 5 requires a kernel rebuild after changing pretty much *anything* !

Cheers,

Rob

[Ivan Ferreira · Accepted solution]

Use sysconfig -Q , for example:

sysconfig -Q vm

If the op= shows a R, can be changed at "Run time".

[Kapil Jha]

Found good information !!!
Closing