Mike,

grub.conf has the line default=1 in it. The complete file follows:

# grub.conf generated by anaconda # # Note that you do not have to rerun grub after making changes to this file # NOTICE: You have a /boot partition. This means that # all kernel and initrd paths are relative to /boot/, eg. # root (hd0,0) # kernel /vmlinuz-version ro root=/dev/cciss/c0d0p6 # initrd /initrd-version.img #boot=/dev/cciss/c0d0 default=1 timeout=10 splashimage=(hd0,0)/grub/splash.xpm.gz title CentOS (2.4.21-27.0.2.EL) root (hd0,0) kernel /vmlinuz-2.4.21-27.0.2.EL ro root=LABEL=/ initrd /initrd-2.4.21-27.0.2.EL.img title CentOS (2.4.21-27.0.2.ELsmp) root (hd0,0) kernel /vmlinuz-2.4.21-27.0.2.ELsmp ro root=LABEL=/ initrd /initrd-2.4.21-27.0.2.ELsmp.img title CentOS (2.4.21-27.0.1.EL) root (hd0,0) kernel /vmlinuz-2.4.21-27.0.1.EL ro root=LABEL=/ initrd /initrd-2.4.21-27.0.1.EL.img title CentOS (2.4.21-27.0.1.ELsmp) root (hd0,0) kernel /vmlinuz-2.4.21-27.0.1.ELsmp ro root=LABEL=/ initrd /initrd-2.4.21-27.0.1.ELsmp.img title CentOS release 3.3 (2.4.21-20.EL.c0smp) root (hd0,0) kernel /vmlinuz-2.4.21-20.EL.c0smp ro root=LABEL=/ initrd /initrd-2.4.21-20.EL.c0smp.img title CentOS release 3.3-up (2.4.21-20.EL.c0) root (hd0,0) kernel /vmlinuz-2.4.21-20.EL.c0 ro root=LABEL=/ initrd /initrd-2.4.21-20.EL.c0.img

What I don't understand is why the System.map symbolic link is changed.

Regards, Wayne

On Mon, 24 Jan 2005 22:45:59 -0600, Mike Kercher mike@camaross.net wrote:

Wayne Bastow wrote:

...

Hi,

I have updated the kernel to 2.4.21-27.0.2 on Centos 3.4 (was 3.3 when I did the kernel update) and have modified grub.conf to use the single CPU kernel:

# grub.conf generated by anaconda # # Note that you do not have to rerun grub after making changes to this file # NOTICE: You have a /boot partition. This means that # all kernel and initrd paths are relative to /boot/, eg. # root (hd0,0) # kernel /vmlinuz-version ro root=/dev/cciss/c0d0p6 # initrd /initrd-version.img #boot=/dev/cciss/c0d0 default=1 timeout=10 splashimage=(hd0,0)/grub/splash.xpm.gz title CentOS (2.4.21-27.0.2.EL) root (hd0,0) kernel /vmlinuz-2.4.21-27.0.2.EL ro root=LABEL=/ initrd /initrd-2.4.21-27.0.2.EL.img title CentOS (2.4.21-27.0.2.ELsmp) root (hd0,0) kernel /vmlinuz-2.4.21-27.0.2.ELsmp ro root=LABEL=/ initrd /initrd-2.4.21-27.0.2.ELsmp.img title CentOS (2.4.21-27.0.1.EL) .......

I then created a new symbolic link for Sytem.map in /boot to point to System.map-2.4.21-27.0.2.EL.

When I reboot the 2.4.21-27.0.1.ELsmp is used and System.map has been changed to point to the smp kernel.

Is there a step I'm missing out?

BTW, the upgrade from 3.3 to 3.4 using yum seems to have worked - I'm running Oracle on the server.

Thanks, Wayne _______________________________________________ CentOS mailing list CentOS@caosity.org http://lists.caosity.org/mailman/listinfo/centos

Perhaps you need:

default=1

You only pasted one entry from your grub.conf. Do you have more entries?

Mike

---

CentOS mailing list CentOS@caosity.org http://lists.caosity.org/mailman/listinfo/centos

Thanks, Simon, that did it.

Wayne

On Tue, 25 Jan 2005 17:51:47 +1300, Simon Garner sgarner@expio.co.nz wrote:

On 25/01/2005 5:40 p.m., Wayne Bastow wrote:

...

Hi,

I have updated the kernel to 2.4.21-27.0.2 on Centos 3.4 (was 3.3 when I did the kernel update) and have modified grub.conf to use the single CPU kernel:

# grub.conf generated by anaconda # # Note that you do not have to rerun grub after making changes to this file # NOTICE: You have a /boot partition. This means that # all kernel and initrd paths are relative to /boot/, eg. # root (hd0,0) # kernel /vmlinuz-version ro root=/dev/cciss/c0d0p6 # initrd /initrd-version.img #boot=/dev/cciss/c0d0 default=1

You just need to change this to default=0, to have the first listed image be the default.

-Simon _______________________________________________ CentOS mailing list CentOS@caosity.org http://lists.caosity.org/mailman/listinfo/centos

I always keep both the SMP and non-SMP kernel because sometimes the smp kernel doesn't work. Let's face it, SMP is still something that isn't rock-solid in linux.

Ben

Beau Henderson wrote:

1. Why the SMP and NON-SMP kernel ? Just one or the other is needed,

not both. SMP = multi-processor or hyperthreading only ( though may be fine with non SMP .. I haven't examined the .config or the sources ). 2. Why the manual Sytem.map to System.map-2.4.21-27.0.2.EL symlink, also note the spelling.

donavan nelson wrote:

Benjamin J. Weiss wrote:

...

I always keep both the SMP and non-SMP kernel because sometimes the smp kernel doesn't work. Let's face it, SMP is still something that isn't rock-solid in linux.

Your experiences differ greatly from mine. What are you doing that can be directly attributed directly to SMP in the kernel?

Thanks,

A few kernel versions back I was trying to capture video from my MiniDV camcorder and then edit the video. When I tried it in SMP, the system would either hang, kernel panic, or reboot. None of those things happened with the uni-processor kernel. I'm running a P4 3GHz with HyperThreading.

I haven't had time to mess with the video editing for the last six months, so thing might have been fixed. But my last experience with the SMP kernels was less than stellar.

Ben

On Tue, Jan 25, 2005 at 08:10:11AM -0600, donavan nelson wrote:

Benjamin J. Weiss wrote:

...

I always keep both the SMP and non-SMP kernel because sometimes the smp kernel doesn't work. Let's face it, SMP is still something that isn't rock-solid in linux.

Your experiences differ greatly from mine. What are you doing that can be directly attributed directly to SMP in the kernel?

Actually, this weekend one of my CentOS 3.3 systems, with two Xeons, ended in some strange state while doing heavy calculations. All seemed normal but one couldn't ssh to the system anymore. After a reboot, the atop datafiles (if you don't know, an enhanced top: http://www.atcomputing.nl/Tools/atop ) showed that after some moment there wasn't any CPU activity anymore. Stronger: it had 0% idle time _and_ 0% user time _and_ 0% sys time. But it didn't hang, there was some activity, for example, yum cron updates where going on. Also note that after the idle/user/sys went to zero, new processed didn't get an proces id anymore and where displayed in atop with proces id '?'.

FWIW: my wild guess was some bug in SMP or SMT stuff.

Regards,

SMP in linux is rock solid..what is causing issues is hyper threading which fakes a second cpu to try to keep it's excessivly long pipeline full. Get two p-3's or two athlon's or run the two p-4's without hyper threading and smp will work just fine. Hyperthreading is a godod idea that unfortunatly has to be used to patch an inefficient cpu design.

Henk van Lingen wrote:

On Tue, Jan 25, 2005 at 03:36:18PM +0100, Henk van Lingen wrote:

...

Also note that after the idle/user/sys went to zero, new processed didn't get an proces id anymore and where displayed in atop with proces id '?'.

Sorry, the '?' thing is normal. These are ended processes in atop.

Cheers,