[blfs-support] blfs-support Digest, Vol 403, Issue 1

Pierre Labastie pierre.labastie at neuf.fr
Thu Oct 22 21:54:47 PDT 2015


On 23/10/2015 02:51, Bruce Dubbs wrote:
> Paul Rogers wrote:
>>>> ISTR that you also have to update the initramfs/initrd every time
>>>> you build a new kernel.  For some of us, new kernels are a frequent
>>>> occurrence;-)
>>>>
>>>> ĸen
>>>
>>> Updating the initramfs/initrd with every kernel build is something
>>> that I am used to doing on my current Mandriva 2010.2. I've been
>>> building my own kernels for a long time now.
>>>
>>> So I will go ahead and install the initramfs, and later do some kernel
>>> builds with initramfs, and some without.
>>
>> I've built a handful of LFS systems over the past decade and NEVER used
>> an initrd!  The purpose of the initrd is mainly for distros that don't
>> know what kind of hardware they may find, in particular device drivers
>> necessary to boot.  So they build the initrd with the whole kitchen sink
>> as modules.  Then they examine the hardware they have and instantiate
>> the correct modules and pivot.  That lets them have a kernel that
>> DOESN'T have to have said kitchen sink built-in, which makes it huge.
>>
>> But building an LFS system, I KNOW the hardware I have in the particular
>> box, and others I'll want to install on, so I build in the drivers I
>> want.  It's a little bigger than the bare minimum, but that's a tradeoff
>> I gladly make to avoid the whole initrd hassle.
>
> That's right Paul.  Really the only reason for an initrd for an LFS 
> system is for very special things like having the root partition on an 
> LVM setup or an encrypted root partition.  There also might be other 
> even more obscure reasons, but I can't think of any right now.
>
> There is also very little reason to have any modules, however I do 
> sometimes enable them for a class of HW if I don't know which driver 
> is really needed.  After that is figured out, I then go back and clean 
> it up without modules.
>
On BLFS, I have a use case for modules: It may happen that some non very 
useful features of the kernel may be used in some package tests. So you 
need those features for full test coverage, but not for daily use. Then, 
it is possible to build those features as modules and issue a few 
modprobe's before tests.

Pierre


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