Showing results for 
Search instead for 
Did you mean: 

CPU Missing

Frequent Advisor

CPU Missing


I recently upgraded my RHAS3 to RHAS4(update 3). After the upgrade i noticed that the OS was not able to see the second CPU and after digging into the issue i realised that the kernel that was instaled was fro uni and not multi. there is just one entry in grub.conf file and even the proc/cpuinfo file shows just one CPU.

But before the upgrade i could see the second CPU (2 Dual Core)

I am wondering as to why just an upgrade can messup with teh multi CPU kernel not getting installed. Is there a way i can get the OS to see all the CPU's I am afraid to do mush r&d on this as this is one of our heavily used database server, which i cannot afford to go down for a long time.

PS: The diagnostics does not mention about any CPU failure and i can see both CPU's online from my dell Open manager

# 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 (hd0,1)
# kernel /vmlinuz-version ro root=/dev/vg00/rootvol
# initrd /initrd-version.img
title Red Hat Enterprise Linux AS (2.6.9-34.EL)
root (hd0,1)
kernel /vmlinuz-2.6.9-34.EL ro root=/dev/vg00/rootvol
initrd /initrd-2.6.9-34.EL.img


[root@innova .gconf]# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Xeon(TM) CPU 3.20GHz
stepping : 3
cpu MHz : 3192.330
cache size : 2048 KB
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm pni monitor ds_cpl cid cx16 xtpr
bogomips : 6388.42
clflush size : 64
cache_alignment : 128
address sizes : 36 bits physical, 48 bits virtual
power management:

Honored Contributor

Re: CPU Missing

up2date -if kernel-smp

This will force the installation of the SMP kernel.

As to why the installation didn't do it on it's own, well.. odd.

Something to be wary of however. If you have oodles of RAM (more than 16GB), you'll want the kernel-hugemem instead. It's SMP aware, and can handle up to 64GB (if memory serves).
One long-haired git at your service...
Frequent Advisor

Re: CPU Missing


I shall try doing that but with my fingers crossed, hoping it does not fiddle with my current setup.

I just have 4 GB of RAM on the box.
Honored Contributor

Re: CPU Missing

i too recently completed a similar upgrade from Red Hat Enterprise Linux AS release 3 (Taroon Update 8)/2.4.21-32.0.1.ELsmp to Red Hat Enterprise Linux AS release 4 (Nahant Update 4)/2.6.9-42.ELsmp w/o any issues.

I do have only 4GB MEM
Honored Contributor

Re: CPU Missing

Upgrade the Kernel (use â i instead of â U, as we want to keep the copy of OLD Kernel rather than upgrading it) Use "Install the Kernel" to emhasize that it is not a replacement but installing a new kernel.
If the system is multiprocessor, then install the kernel-smp packages, and upgrade the kernel-utils packages.

Install the newer kernel pacakge by rpm -i & rpm -u kernel-utils*. Installing the new kernel (rpm -i) will help to roll back to the old kernel by updaing the /boot/grub/grub.cong to the required one.

Frequent Advisor

Re: CPU Missing

Thanks Guys,

I have installed the recommended rpm's and it has made the entry into the grun.conf automatically . I havent got a chance to reboot the box yet, but i am hoping that this will resolved the issue. Thanks for all youe help
Frequent Advisor

Re: CPU Missing

Installing the SMP kernel packages works . Thanks