Is CentOS 4.3 , kernel 2.6.9-34 stable ?

The kernel is not the only cause of high server load on a CentOS server. Down/upgrading might help, in your case you need to go after the source of the trouble. I suggest you search these forums since this issue has been discussed so many times. Good luck!

 

kernel-2.6.9-40 is the latest and most stable version. We upgraded our clients' kernel to this release and works just fine. If you are interested in learning more about high server load, read this thread: http://forums.cpanel.net/showthread.php?t=50421 Hope this helps!

 

It is possible to compile latest kernel 2.6.17.3 from source on production server without any problems.


Tutorial - http://webhostingtalk.com/showthread.php?t=489019&highlight=update+kernel+on+centos+4



Default CentOS 4 kernel 2.6.9-22 has a lots of problems and bugs with I/O and swapping...

 

I have excactly the same problem !

My host has also swapped my hardware (PERFECT SERVICE !) and the problem stays.
When disabling EXIM i can hold the server under control. I only start exim once in a while.

The server worked fine until several weeks ago, i am going to check if i can see when the kernel was updated.

Is the solution up-down grading the kernel ?

Thanks

 

I upgraded several servers with load problems (all Centos) to 2.6.9-39.0.2.EL


and they are now all calm and nice again.

 

Yes, it is possible, but it depends on the level of expertise with Linux/FreeBSD OS. If you compile Kernel from source, and just in case it didn't work, you can always switch back to the previous working version you had.

 

Well, http://people.redhat.com/~jbaron/rhel4/RPMS.kernel/ contains now a 2.6.9-42 kernel.
Having the same issue with 2.6.9-34 kernel, i've installed it and rebooted.
All went smooth and worked perfect (please note that is a personal oppinion, not an advice).

 

The original source file of this kernel is:
ftp://ftp.redhat.com/pub/redhat/linux/updates/enterprise/4ES/en/os/SRPMS/kernel-2.6.9-42.EL.src.rpm

You can compile this kernel or use the kernel that gupi wrote.

 

Same here, going to this kernel fixed my woes for a couple boxes.

 

I have upgraded a couple of my servers to 2.6.9-39.0.2.ELsmp and it is WAY WAY WAY better...see this thread: http://forums.cpanel.net/showthread.php?t=56045

The upgrade is very easy too, you just download the RMPs from the testing area on centOS. I have developed the following set of instructions if you are using grub as your os loader:

Code:

cd /var/spool/up2date

wget http://dev.centos.org/centos/4/testing/i386/RPMS/kernel-2.6.9-39.0.2.EL.i686.rpm
wget http://dev.centos.org/centos/4/testing/i386/RPMS/kernel-devel-2.6.9-39.0.2.EL.i686.rpm
wget http://dev.centos.org/centos/4/testing/i386/RPMS/kernel-hugemem-devel-2.6.9-39.0.2.EL.i686.rpm
wget http://dev.centos.org/centos/4/testing/i386/RPMS/kernel-smp-2.6.9-39.0.2.EL.i686.rpm
wget http://dev.centos.org/centos/4/testing/i386/RPMS/kernel-smp-devel-2.6.9-39.0.2.EL.i686.rpm

rpm -ivh kernel-2.6.9-39.0.2.EL.i686.rpm kernel-devel-2.6.9-39.0.2.EL.i686.rpm kernel-hugemem-devel-2.6.9-39.0.2.EL.i686.rpm kernel-smp-2.6.9-39.0.2.EL.i686.rpm kernel-smp-devel-2.6.9-39.0.2.EL.i686.rpm

Then to be safe, set your server to boot into the new kernel only once:

Code:

vi /boot/grub/grub.conf

in grub, change order of new kernel to second, make the old kernel the first one. Then do the following:

Code:

grub

wait a few seconds for this to come up, then type the following lines

Code:

savedefault --default=1 --once
quit

then reboot your server and check to see if the new kernel was successful:
uname -r

if it is then edit grub.conf so that the new kernel is the first in the list. If this does not work, simply reboot / power cycle and you should come up with your old kernel.

Good luck, use these instructions and this test kernel AT YOUR OWN RISK!!!

 

Redhat released the official kernel-2.6.9-42.
This is the latest stable kernel for RHEL4 (and CentOS 4.3).

We have compiled and installed this kernel on one of our servers.
Now we are testing the performance.
I will notify you about the performance.

If anyone interests on compiling this kernel, see below:

Code:

wget ftp://ftp.redhat.com/pub/redhat/linux/updates/enterprise/4ES/en/os/SRPMS/kernel-2.6.9-42.EL.src.rpm
rpm -ihv kernel-2.6.9-42.EL.src.rpm

The sources of the kernel is now in /usr/src/redhat

Code:

cd /usr/src/redhat
rpmbuild -bb --target=i686 SPECS/kernel-2.6.spec

It takes about 30 minutes to compile the kernel. After a successfull compile, the new kernel rpms are located on "/usr/src/redhat/RPMS/i686" folder.

Code:

-rw-r--r--  1 root root  11327798 Aug 14 05:27 kernel-2.6.9-42.EL.i686.rpm
-rw-r--r--  1 root root 316150714 Aug 14 05:53 kernel-debuginfo-2.6.9-42.EL.i686.rpm
-rw-r--r--  1 root root   3880571 Aug 14 05:27 kernel-devel-2.6.9-42.EL.i686.rpm
-rw-r--r--  1 root root  10818123 Aug 14 05:29 kernel-hugemem-2.6.9-42.EL.i686.rpm
-rw-r--r--  1 root root   3906847 Aug 14 05:29 kernel-hugemem-devel-2.6.9-42.EL.i686.rpm
-rw-r--r--  1 root root  10939279 Aug 14 05:28 kernel-smp-2.6.9-42.EL.i686.rpm
-rw-r--r--  1 root root   3897131 Aug 14 05:28 kernel-smp-devel-2.6.9-42.EL.i686.rpm

You can now install what kernel you want.

 

UPDATE:

Now it is peak time for the server that we upgraded and it seems working perfectly.

 

You can download it from:
ftp://ftp.redhat.com/pub/redhat/linux/updates/enterprise/4ES/en/os/SRPMS/

If you want you can download the packages that i compiled from http://www.trhosting.net/kernel/

These packages are for Centos 4.x i686

 

No need now, since CentOS have released the 2.6.9-42.0.2 kernel for v4 now. You can get it from your freindly yum mirror

 

Does anyone know why cpanel service fails to start when centOS is booted with kernel 2.4.33?

thanks

 

Hi all.

I'm currently running Dual Xeons.

Do dual processor systems require different 'type' of kernel?

I tried other kernels in the past but they don't work.

I'm currently using the default 2.6.9-34.ELsmp from the default CentOS 4.3 installation.

Please advise!

Thank you..

 

They simply need to smp kernel. You should be able to use the latest CentOSv4 kernel unless you have RAID hardware or the like that the manufacturer hasn't bothered supporting (there are a few). The kernel you are running (2.6.9-34.ELsmp) is now old and vulnerable to root escalation compromises.