2014/08/18 14:57 Christopher Chavez 2000...@gmail.com:
(Please let me know if there's a better venue for collecting feedback for
this
idea, or additional ones I should solicit feedback from. I primarily use
Ubuntu,
but I assume this is as upstream as it gets.)
Upstream relative to what? Boot managers have their own projects and
mailing lists.
Background:
It has been discussed (in other venues) where a separate /boot partition
(e.g.
for btrfs, LVM, and encrypted installations; or to workaround BIOS
limitations),
depending on how large it was when created, will have a likelihood of
becoming
full after multiple kernel updates, and there are corresponding bug
reports
likewise (which I have not listed here).
debian, at any rate, has not had problems with old kernels filling up the
/boot partition for a long time. I don't care for the way it's being done,
but it pretty much works.
One proposed measure was to not use a /boot partition in the first place,
which
often works, but I have also managed to have installations fail with
core.img
is unusually large, particularly in instances where the disk was
pre-formatted,
including Windows multiboot scenarios.
I generally never bothered with a separate /boot on i386 back in the days
of Fedora 4 or so, but I knew my BIOS could see the whole drive.
openbsd uses a different partitioning scheme and a different way to boot,
fits the boot-up code and all the openbsd partitions within a single BIOS
recognized partition. It uses a kind of relay or trampoline technique, so
the code that the BIOS passes control off to doesn't ever have to move.
Grub 1 was kind of like that, too, but in a different way. openbsd can boot
without a boot manager, but the whole purpose of grub is to hand off the
boot to something else.
Questions:
1. Is it the case that the only reason for having a separate /boot was to
provide easy access /boot/grub? I.e., was it intentional to provide easy
access
to kernels as well?
I guess it depends on what you mean by easy access. If you mean, to keep
the kernel where it can be easily found by the boot manager, yeah, that's
one of the big reasons.
That information used to be a lot more available, until some IPidiots
started trying to claim rights to it. But you can still find it on
wikipedia. But I think your question was answered in the chat session you
quoted below. And elsewhere in this thread.
It occurs to me that putting grub in its own partition might make it easier
for the various distros to cooperate about updating the grub configuration
file. But I don't know if anyone is working on that. I would definitely not
do it with the old BIOS partitions. Not enough partitions to work with.
2. Would it be a better idea to only have /boot/grub, instead of /boot,
on a
separate partition? (I can confirm that it works both when installing and
in
existing setups, i.e. grub-install and update-grub both work as expected.)
Have you found a way to tell each distro to use the independent grub?
3. If so, then what should its size be? Does it vary by installation and
is it
expected to grow over time? (In my case it requires ~5MB for i386, so I
used a
~30MB ext4 partition. I have not considered UEFI, e.g. if using the ESP is
better.)
Have you looked at the grub project's site?
I attempted to collect some preliminary feedback on IRC (the following was
logged publicly):
#ubuntu, 25 Jul 2014:
[00:50] chrstphrchvz Does the size of /boot/grub vary by installation
or
over time, making it undesirable for separate partition? see
description:
http://ur1.ca/htmwi(Unsure if a support or development question, since I
am
seeking knowledge/opinion.)
[00:52] TJ- chrstphrchvz: Yes, it can vary slightly as newer kernels
are
installed, if older kernels aren't also removed. I generally use a 512MB
/boot/ file-system partition
[00:56] Bashing-om chrstphrchvz: A separate /boot is something of an
anachronism, dating back to limited PC BIOSes that could only handle
small
disks, so the boot files had to be at the start of the disk. Nowadays,
this is
no longer applicable .
^^^*^^^
[00:57] chrstphrchvz TJ-, I mean specifically /boot/grub rather than
/boot
(i.e. as an alternative). E.g. I can keep /boot on my root partition,
and use
a separate /boot/grub, but is a good idea? (I know it works.)
[00:58] TJ- chrstphrchvz: You're asking to confuse GRUB, since it
expects
/boot/ and /boot/grub/ to be in the same root file-system
or, more specifically, the grub configuration updater tool.
[00:59] TJ- chrstphrchvz: but specifically, grub/ doesn't vary much
in size,
it contains the GRUB loadable modules, the saved environment, and
grub.cfg
[01:04] chrstphrchvz Bashing-om, GRUB is (theoretically) able to boot
LVM
etc. (what it is typically installed with nowadays) without a /boot
partition,
but it can result in core.img unusually large and failing to install
(see
description for cases).
[01:06] chrstphrchvz TJ-,
