Re: [gentoo-user] Re: LVM, /usr and really really bad thoughts.

[Mark Knecht]

On Thu, Mar 15, 2012 at 6:56 AM, Tanstaafl <tanstaafl@×××××××××××.org> wrote:
> On 2012-03-15 9:05 AM, Neil Bothwick <neil@××××××××××.uk> wrote:
>>
>> On Thu, 15 Mar 2012 08:41:38 -0400, Tanstaafl wrote:
>>
>>>> That's why I build the initramfs into the kernel and not as a separate
>>>> file. If I do something to break the initramfs I just boot the
>>>> previous kernel knowing it will still work.
>>>
>>>
>>> Ok, time to show my ignorance...
>>>
>>> How would I know if I am using an initramfs, and if I was, whether it
>>> was built into the kernel or not?
>
>
>> Well, you built the kernel, so you should know.
>
>
> Well, since I basically just used a kernel .config that someone else
> originally set up, copying .config over and running make oldconfig when
> upgrading over the years, stumbling through any changes that broke anything
> (like when some changes to iptables broke my firewall back around 2.6.2x), I
> really didn't know - but I just confirmed that it is indeed built into my
> kernels, so, now, how do I know if I am *using* it or not?
>
>
>> Technically, we are all using an initramfs as all 2.6/3 kernels mount an
>> initramfs when they load. If does not contain an init script, they fall
>> back to the legacy behaviour.
>
>
> So, how do I know whether or not 'it contains an init script'?
>
> I know, my ignorance is confounding...
>
>> See /usr/src/linux/Documentation/filesystems/ramfs-rootfs-initramfs.txt
>
>
> Read it, thanks, but it didn't help me answer the above...
>

I've only used an initramfs/initrd once so I can relate to the
confusion. Assuming you have the config in /proc run:

c2stable ~ # zcat /proc/config.gz | grep INITRAMFS
CONFIG_INITRAMFS_SOURCE=""
c2stable ~ #

Also, if you didn't actually create the initramfs hierarchy and zip it
up to be used by your kernel then you're not using one, other than
what Neil said that we all use one that does nothing.

HTH,
Mark