kernel configuration backup

[Subentu]

hi guys

I have a Rx1720 server running HP-UX 11.2vi

I recently changed the following 5 kernel parameters.
1. ninode
2. physical_io_buffers
3. shmseg
4. swapmem_on
5. vx_ninode

To my understanding, the old kernel configuration should be saved in the /stand/backup directory when the changes were made. But it did not.

Can you please explain.

Thanks and Regards

[Jeeshan]

Hi Subentu

i suggest you to take a full OS backup (ignite) before proceeding the kernel parameter changes.

this will keep you almost relief of revert back or recovery.

[Subentu]

I did take a full ignite tape backup. But I'm puzzled why it did not backup the kernel configuration in /stand/backup

[Jeeshan]

did you found anything like system.old in /stand file system. that is your old kernel.

[Subentu]

thanks for the reply

this is the output of the #ll /stand:

total 106864
drwxr-xr-x 5 root sys 8192 Jun 26 11:10 backup
dr-xr-xr-x 3 bin bin 96 Sep 8 2004 boot.sys
-rw-r--r-- 1 root sys 42 Jul 3 2005 bootconf
lrwxr-xr-x 1 root root 14 Jun 26 11:31 bootfs -> current/bootfs
drwxr-xr-x 5 root root 8192 Apr 8 10:05 crashconfig
drwxr-xr-x 5 root sys 8192 Dec 12 2007 current
drwxr-xr-x 5 root sys 8192 Jun 10 2007 good
-rw-rw-rw- 1 root sys 18728 Jun 26 16:57 ioconfig
-r--r--r-- 1 root sys 82 Sep 8 2004 kernrel
drwxr-xr-x 2 root sys 96 Jun 26 11:35 krs
drwxr-xr-x 5 root sys 8192 Sep 8 2004 last_install
drwxr-xr-x 2 root root 96 Apr 13 2005 lost+found
lrwxr-xr-x 1 root root 7 Jun 26 11:31 nextboot -> current
-rw------- 1 root root 12 Jun 26 11:31 rootconf
lrwxr-xr-x 1 root root 15 Jun 26 11:31 system -> nextboot/system
-r--r--r-- 1 root sys 2375 Apr 13 2005 system.import
-rw-r--r-- 1 root sys 3621 Dec 12 2007 system.prev
-rwxr-xr-x 4 root sys 54602784 Dec 12 2007 vmunix



and this is the output of #ll /stand/backup:

total 106704
-rw-r--r-- 1 root sys 147 Jun 26 11:10 README
drwxr-xr-x 3 root sys 96 Jun 26 11:10 bootfs
drwxr-xr-x 2 root sys 96 Jun 26 11:10 krs
drwxr-xr-x 2 root sys 8192 Jun 26 11:10 mod
-rw-r--r-- 1 root sys 3731 Jun 26 11:10 system
-rwxr-xr-x 4 root sys 54602784 Dec 12 2007 vmunix


The changes were done on 26th June 2008.

Any idea where the old kernel might be?

[Dennis Handly]

>The changes were done on 26th June 2008.
>Any idea where the old kernel might be?

You can always do a find:
$ find /stand -name "*vmunix*"

[Don Morris_1 · Accepted solution]

The vmunix file can be unchanged in multiple configurations if you're only changing parameters [the binary doesn't need to change in post-11.11 releases, tunables don't get recompiled into the kernel, they're read in and applied as appropriate].

First question -- how did you do the kernel tunable changes? kctune? SAM? SMH? If kctune -- did you use the "-b" flag at all?

Second question, what does "kctune shmseg" and "kctune -c backup shmseg" report?

[Tim Nelson]

Note your system file has changed in the backup directory.

-rw-r--r-- 1 root sys 3731 Jun 26 11:10 system


As mentioned not every tune requires a new kernel.

[Subentu]

I used SAM to do the changes.

#kctune shmseg
Tunable Value Expression Changes
shmseg 300 Default Immed

#kctune -c backup shmseg
Tunable Value Expression
shmseg 300 Default

[Tim Nelson]

One last item.

kclog is a great command to see a history of kernel changes.