/boot filesystem

[Goh Lip]

On Tuesday 23,November,2010 03:47 PM, Tom H wrote:
> On Tue, Nov 23, 2010 at 1:33 AM, Mark<mhullrich at gmail.com>  wrote:
>> On Mon, Nov 22, 2010 at 10:12 PM, Tom H<tomh0665 at gmail.com>  wrote:
>>>
>>> I don't think that anyone needs to try "update-grub" or
>>> "update-initramfs ..." with "/boot" unmounted. It won't work. :)
>>>
>> Oh, it probably will, just not the way you expect - see my prior email
>> about what happens when you mount over a "live" directory (or, in this
>> case, don't).
>
> Thanks, had missed that email - and that subtlety. Good catch.
> "update-grub" will write to the "/boot" directory and apt-get will
> save a new kernel there but an "update-initramfs ..." unrelated to a
> kernel newly installed into the "/boot" directory will fail.

On Tuesday 23,November,2010 02:23 PM, Tom H wrote:
 > Goh Lip should probably call his "boot" partition a grub partition...


This is not a rebuttal nor disagreement, perhaps a clarification 
probably due to the poor choice of terminology (I used).....

Imagine having 3 ubuntu-like OS's, (ie no grub-l, no dev by uid) all set 
to mbr. All having their own /boot partitions. Naturally only one, the 
last having grub-update, will actually be set to mbr. Call this OS-M; 
the other 2, OS-O1 and OS-O2.

Note that /boot of OS-M contains kernels of OS-M but never any kernel of 
OS-O1 or OS-O2.

Let's say we boot OS-O1, naturally from the /boot of OS-M. At this 
point, /boot of OS-M will not be mounted, even though it is the one 
doing the booting, and should be called the 'boot partition', right? 
Even if it is not the /boot for OS-O1.

Now, let's say we grub-update OS-O1 due to new kernel. /boot of OS-M 
will be totally untouched and unaffected (hence still listing old kernel 
of OS-O1). Note however, the /boot of OS-O1 will now be set to mbr and 
will become the one booting up all the OS's.

So to clarify further to Rashkae's query, what I've done is to create an 
independent 'grub'/'boot'/'whatever' partition that needs no kernels 
that is set to mbr that boots everything. Nothing else will be set to 
mbr because my OS's are all set to /dev/sdaX instead of /dev/sda and 
grub-update will not set these to mbr, ever.

Regards and cheers - Goh Lip