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Re: ext2 for /boot ???




On 2018-09-12 13:50 -0500, David Wright wrote:

> On Wed 12 Sep 2018 at 11:36:22 (+0200), Sven Joachim wrote:
>> On 2018-09-12 10:11 +0100, Jonathan Dowland wrote:
>> > On Tue, Sep 11, 2018 at 11:32:56PM -0400, Lee wrote:
>> >>Just out of curiosity - why would journaling be undesirable on a
>> >>partition that is almost never written to?
>> >
>> > …I'm not sure what the answer to your question is, but with regards
>> > /boot and filesystems: on one EFI host of mine, I had a lot of problems
>> > with /boot/efi precisely because it couldn't be journalled (mandated to
>> > be vfat) and I had filesystem issues with it after every unscheduled
>> > power failure. I ended up bodging my system to mount it read-only by
>> > default, and had to add some apt hooks to remount it writeable for a
>> > selection of packages (e.g. new kernel, basically anything that might
>> > trigger an initramfs rebuild)
>> 
>> This sounds like you put /boot/efi on the same filesystem as /boot which
>> is not recommended or supported at all[1].  On my laptop there is only a
>> single file under /boot/efi, namely /boot/efi/EFI/debian/grubx64.efi -
>> which will be written to on updates to the grub-efi package, but not
>> when installing a new kernel or rebuilding an initramfs.
>> 
>> 1. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=163988
>
> I read through this and couldn't work out its relevance. My boot
> partition doesn't contain any hard links: the link counts are all 1.
> The problem mentioned in the bug report (hard links are necessary to
> conserve space) would be irrelevant as there's so little demand for
> space in /boot.

Sorry, I should have linked to the merged bug[1] instead which makes the
issue a bit more clear.

> Now I think I can see the temptation to put all of /boot into the ESP:
> mine contains a tree of files under grub/ plus the eight kernel files
> one would expect—nothing that appears to conflict with a VFAT
> filesystem—so the EFI directory would fit nicely there.
>
> Examining the real ESP on this PC, I don't see any potential for name
> clashes between the windows files in there and what Debian users
> report is in their own ESPs (which appear to be safely stowed under
> the directory debian/).
>
> So what are the arguments against doing this (which I accept there may
> well be)? We'll ignore the eyebrow-raising need for /boot to be
> journalled, shall we?

The killer argument is that you can install new kernels that way but not
update them, because dpkg requires the filesystem to support hardlinks
for that.  Read Guillem's replies in [1].

Cheers,
       Sven


1. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=825945