[nylug-talk] [NYLXS - HANGOUT] Re: Benefits/drawbacks of building Linux as a package [was: Looking for recommendations on Linux Distro]

[Chris Knadle]

On Sunday 16 March 2008, Michael Werneke wrote:
> And as far as package management goes for kernels, I gave up on compiling
> my own kernels a long time ago. I found that they were just not worth the
> effort for my own uses.  When apt (and now aptitude) install new kernels,
> they both keep the old kernels and then put the newest kernel at the top of
> the grub.conf so if the new kernel happens to panic, or just won't boot
> properly I can just reboot and pick the next kernel on the list. As far as
> there being issues with pre-packaged kernels, the only ones I've had have
> been with obscure and antiquated hardware.

   Just to clear up confusion -- when I brought up pre-packaged kernels, what 
I meant was the kernels that are within the distro's repository.  I.E. when 
apt installs a new kernel, I consider that to be "pre-packaged" [by the 
maintainer or kernel team], as opposed to compiling your own kernel to a 
package.

> I have a DEC Alpha running Debian Sarge and the initrd had been pointing
> to the wrong place to find the / partition. I don't remember what the
> workaround was, but shortly thereafter there was an update to the installer
> and it Just Worked(tm) after that. Your mileage may vary.

   Huh.  Weird!
   Grub should pass the partition for / as a parameter to the kernel; 
I.E. "root=/dev/<device>".  If somehow the initrd image used some other 
device name than the parameter that was passed in, that would certainly be 
curious.
   I've likewise run into that problem because I had the wrong settings for 
the entry in /boot/grub/menu.lst:

     # kopt=root=/dev/hde3 ro vga=1

   So even though that looks like a comment, if the wrong root device is 
specified, the next time 'update-grub' is run, the root device on all of the 
entries will be replaced with the setting above.  This happens (relatively) 
often when transferring an installed system to a new disk but rearranging 
partitions so that the root filesystem is on another partition than it was 
originally.

   Ubuntu seems to do this slightly differently, where the device specified is 
the UUID of a partition rather than a device name; the benefit is that if the 
device name changes grub can find the partition to pass in for the kernel to 
mount -- but the drawback naturally is that if the data is copied over to a 
new drive, the new partition is likely going to have a new UUID so the system 
may not boot.  [I have NOT tested this.]



   Re: grub.conf vs menu.lst -- I didn't even notice because at one time it 
was common for there to be a preinstalled grub.conf softlink to the menu.lst 
file, which doesn't seem to be commonly made anymore.

   -- Chris

-- 

Chris Knadle
Chris.Knadle at coredump.us