topic Re: Kernel Modification in Operating System - HP-UX

Kernel Modification

Geno Church_1 — Thu, 18 Mar 2004 10:59:07 GMT

Folks,

I need some help here. I need to modify the kernel parameter nstrtel. This parameter is responsible for the number of allowable telnet sessions. Currently it is set to 60 and I want to increase it to 120. I don't want to use SAM for this because I need to put together a script to push this out to several systems. Could someone post a step by step command line instruction on how to modify the kernel and move the new kernel in place I would greatly appreciate it and will definitly award points! ;)

Thanks in advance,
Geno

Re: Kernel Modification

Steven E. Protter — Thu, 18 Mar 2004 11:08:58 GMT

kmtune -q query

kmtune -s sets it

so:

kmtune -s npty=120
kmtune -s nstrpty=120

cd /stand/build
/usr/lbin/sysadm/system_pre -s system
mk_kernel -s system
kmupdate

mv /stand/vmunix.prev vmunix.prev.1
mv /stand/vmunix vmunix.prev
mv vmunix /stand/vmunix

SEP

Re: Kernel Modification

Geno Church_1 — Thu, 18 Mar 2004 11:16:28 GMT

Would I run the kmtune commands before the system_prep command or after?

Re: Kernel Modification

Michael Schulte zur Sur — Thu, 18 Mar 2004 11:22:37 GMT

Hi,

I would say, SEP posted it in the sequence, you would use it too, except for that missing p.

greetings,

Michael

Re: Kernel Modification

RolandH — Thu, 18 Mar 2004 11:28:39 GMT

Check also that you have enough pty devices

# ls /dev/pts/t* | wc -w

If the value is lower as 120
then you must increase the number of device files.
In this case this will not be done if you reboot after kernel modification.

# # insf -d tels -s 120

Regards
Roland

Re: Kernel Modification

Geno Church_1 — Thu, 18 Mar 2004 11:33:47 GMT

SEP,

Thanks for the inof...BTW...I'm a little concerned about the kmtune placement...I was under the assumption the kmtune is ran after system prep.

Thanks again.

Geno

Re: Kernel Modification

Michael Schulte zur Sur — Thu, 18 Mar 2004 12:25:09 GMT

Hi,

the kmtune placement seems to be right.
However I have a problem with the last mv.
I got only a vmunix_test in /stand/build.

SEP, could you verify that?

Michael

Re: Kernel Modification

Steven E. Protter — Thu, 18 Mar 2004 12:34:06 GMT

Yes, two mistakes.

Someone was talking to my while i posted.

system_prep not system_pre

and yes, Michael, when i actually bothered to run the commmands i got vmunix_test

Please modify my procedure accodringly and award this post 0 points.

SEP

Re: Kernel Modification

Michael Schulte zur Sur — Thu, 18 Mar 2004 12:49:32 GMT

SEP,

in anticipation of that I moved vmunix_test to /stand. Then however upon reboot I got in /etc/rc.log an error that it could not find /stand/build/vmunix_test.

Have I missed anything?

greetings,

Michael

Re: Kernel Modification

Geno Church_1 — Thu, 18 Mar 2004 15:08:18 GMT

Ok folks,

I have tried this procedure and it hasn't worked...If I do a kmtune -q nstrtel it still shows the pending value to be what I set it to and the current value is still the same....The procedure doesn't call for moving the /stand/system to /stand/system.prev..does this need to be done....If so, does a new /stand/system get created?

Geno

Re: Kernel Modification

RolandH — Fri, 19 Mar 2004 04:38:11 GMT

Ok - point for point.
This is the procedure for 11.00 & 11.11

1.# cd /stand/build
# rm â r * (Be careful with this! You need to be in /stand/build/)

2) Backup the current system file:
# cp /stand/system /stand/system.prev

3) Is the system file up to date?
If you are not sure that the current system file (/stand/system) corresponds to
the current kernel (/stand/vmunix), then use the system_prep script to extract a
system file from the current kernel:
# /usr/lbin/sysadm/system_prep [-s /stand/system]
Compare the new system file to the original one. The diff command should not
produce any results:
# diff /stand/system /stand/system.prev

4) Modify the system file
Use kmtune(1M) to modify kernel tunables. Use kmsystem(1M) to add/remove driver.
These commands do nothing more than modifying /stand/system. Due to various
dependencies, the system file should not be edited by hand. E.g.:
# kmtune â s dbc_max_pct=35 (changes tunable in system files)
# kmsystem â c y diag2 (adds driver diag2 to system file)
# kmsystem â c n diag2 (removes driver diag2 from system file)
The â kmâ commands are explained below in greater detail.

5) Generate the kernel
After you modified the system file, you can generate the new kernel using the
mk_kernel script. The name of the new kernel will be /stand/build/vmunix_test,
unless explicitly specified through the -o option. The -s option specifies the system file
to use, /stand/system is the default:
# mk_kernel

6) Schedule kernel update
kmupdate is used to initiate the move of the new kernel (/stand/build/vmunix_test)
and the corresponding files to their appropriate places at the next shutdown or startup.
The current kernel will be copied to /stand/vmunix.prev, then.
# kmupdate

7) Restart the system
The new kernel will be activated by restarting the system:
# cd /
# shutdown â r 0
NOTE:
Do not use the reboot command. Otherwise the movement of the kernel files will be
skipped and the system boots from the original kernel again. If you really need to reboot
instead of shutdown, then execute the rc script manually before rebooting:
# /sbin/init.d/kmbuild stop

I have attached a document where all these procedures are explained (for 10.x and 11.22/23 systems, too)

Do not assign points to this. SEP has explained the b

Re: Kernel Modification

RolandH — Fri, 19 Mar 2004 04:42:33 GMT

Hopefully in a better readable output now.

Ok - point for point.
This is the procedure for 11.00 & 11.11

1.# cd /stand/build
# rm -r * (Be careful with this! You need to be in /stand/build/)

2) Backup the current system file:
# cp /stand/system /stand/system.prev

3) Is the system file up to date?
If you are not sure that the current system file (/stand/system) corresponds to
the current kernel (/stand/vmunix), then use the system_prep script to extract a
system file from the current kernel:
# /usr/lbin/sysadm/system_prep [-s /stand/system]
Compare the new system file to the original one. The diff command should not
produce any results:
# diff /stand/system /stand/system.prev

4) Modify the system file
Use kmtune(1M) to modify kernel tunables. Use kmsystem(1M) to add/remove driver.
These commands do nothing more than modifying /stand/system. Due to various
dependencies, the system file should not be edited by hand. E.g.:
# kmtune -s dbc_max_pct=35 (changes tunable in system files)
# kmsystem -c y diag2 (adds driver diag2 to system file)
# kmsystem -c n diag2 (removes driver diag2 from system file)

5) Generate the kernel
After you modified the system file, you can generate the new kernel using the
mk_kernel script. The name of the new kernel will be /stand/build/vmunix_test,
unless explicitly specified through the -o option. The -s option specifies the system file
to use, /stand/system is the default:
# mk_kernel

6) Schedule kernel update
kmupdate is used to initiate the move of the new kernel (/stand/build/vmunix_test)
and the corresponding files to their appropriate places at the next shutdown or startup.
The current kernel will be copied to /stand/vmunix.prev, then.
# kmupdate

7) Restart the system
The new kernel will be activated by restarting the system:
# cd /
# shutdown -r 0
NOTE:
Do not use the reboot command. Otherwise the movement of the kernel files will be
skipped and the system boots from the original kernel again. If you really need to reboot
instead of shutdown, then execute the rc script manually before rebooting:
# /sbin/init.d/kmbuild stop

I have attached a document where all these procedures are explained (for 10.x and 11.22/23 systems, too)

Do not assign points to this. SEP has explained the basics before.

Roland

Re: Kernel Modification

Laurent Menase — Fri, 19 Mar 2004 05:08:07 GMT

one precision about the sequence:
mk_kernel -s system
kmupdate

mv /stand/vmunix.prev vmunix.prev.1
mv /stand/vmunix vmunix.prev
mv vmunix /stand/vmunix

Don't do that!
1) kmupdate backup /stand/vmunix to /stand/vmunix.prev
2) if you really want to keep vmunix.prev,
don't forget to move /stand/dlkm.vmunix.prev
to /stand/dlkm.vmunix.prev.1, else your kernel will not be bootable.
3) kmudpate make that the next shutdown will mv /stand/build/vmunix_test to /stand/vmunix, and /stand/build/dlkm_vmunix_test to /stand/dlkm after backing the original ones to prev

Re: Kernel Modification

Geno Church_1 — Fri, 19 Mar 2004 09:24:24 GMT

I think I have it now...I went through the procedure and it now works.....

6972 cd /stand/build

6973 /usr/lbin/sysadm/system_prep -v -s system

6975 kmtune -s nstrtel=120 -S /stand/build/system

6976 kmtune -s npty=120 -S /stand/build/system

6977 kmtune -s nstrpty=120 -S /stand/build/system

6978 mk_kernel -s system

6979 mv /stand/system /stand/system.old

6980 mv /stand/build/system /stand/system

6981 /usr/sbin/kmupdate /stand/build/vmunix_test

6982 cd /

6983 shutdown -ry 0

Once system is back upâ ¦.verify your changesâ ¦..

6984 kmtune -q nstrtel Ã Should now be 120

6986 ls /dev/pts/t* |wc -l <-Should still be 60

6987 insf -d tels -s 120 Ã Will set the ttys to 120

6988 ls /dev/pts/t* |wc -l Ã Should now be 120

Thanks for all th