[CentOS] Centos 6.0 , DRBD

Wed Oct 12 10:16:16 UTC 2011
Ljubomir Ljubojevic <office at plnet.rs>

Vreme: 10/12/2011 07:10 AM, Karanbir Singh piše:
> Hi,
> On 10/11/2011 06:23 PM, Ljubomir Ljubojevic wrote:
>> I do not have to read it (although I understood you the first time). My
> its strange then you feel compelled to comment on something without
> making an effort to even see what the other person is talking about.
>> production server is not going to be a ginipig for developers. And I, so
>> far, rebuilt over 100 packages including newer Qt for C6.
> people with the idea of a 'production' setup usually also understand the
> idea of 'devel' and 'testing'. People who dont have an idea of
> 'production' dont need to care about or are already isolated from
> needing to care about 'devel' and 'testing', isnt it ?
> Just saying.
> - KB

Joseph's post was:

Yeah, but generate rpm's for final installation, its trivial.

End of the link says Build Rpm. So, install building tools and 
environment, and kernel-devel on the production system (5 years ago I 
was thought that it is not wise to do so), and compile it against your 
And there is already built and tested "kmod-" module from ELRepo.

Just so I can answer you (all), I visited that web page and read following:
"Note that any kernel upgrade will require you to generate a new drbd-km 
package to match the new kernel."

So, my assumption that kernel upgrade without rebuilding the module 
would brake his production server was correct.

I used to use madwifi-kmdl kernel modules for my Atheros wireless radio 
card, and each time I upgraded kernel I had to upgrade/install new 
module also. Very tiresome.

Then I studied kmdl vs kmod packages and learned that kmod packages do 
not need any recompilation after kernel upgrade. They use "weak-update" 
model (essentially symlinks) as long as new kernel has same ABI as 
previous ones. Install process of new kernel checks kernel modules of 
currently installed kernels and symlinks them, avoiding need for 
building them or installing new packages (hoping they are already 
available). I was delighted when I saw that ELRepo developers use kmod 
model, no more messing with kernel modules.

That is why I suggested using ELRepo kernel module package instead of 
self-built one. Only reason I can see in building your own module is to 
use those other packages (like drbd-heartbeat).

I hope this finally clears up what I tried to say:

1. Joseph's link clearly stated it was for self building the rpm(s) so I 
did not need to visit the link to know what is on the page.

2. Developers of kernel module packages rarely use kmod approach in fear 
people will mess it up (like installing vanila kernel on CentOS sistem 
and still calling it CentOS,...). Ubuntu and Arch users especially have 
this problem, so it is safer to build for each new kernel.

3. Kernel module re-packagers from ELRepo have luxury of safely offering 
kmod packages for EL kernels, and I believe this is safest and best 


Ljubomir Ljubojevic
(Love is in the Air)
PL Computers
Serbia, Europe

Google is the Mother, Google is the Father, and traceroute is your
trusty Spiderman...
StarOS, Mikrotik and CentOS/RHEL/Linux consultant