How to clean up full /boot safely?

[Tom H]

On Mon, Feb 12, 2018 at 3:35 PM, Liam Proven <lproven at gmail.com> wrote:
> On 12 February 2018 at 20:31, Tom H <tomh0665 at gmail.com> wrote:
>>>
>>> Is it possible to give a definite canonical answer to this, without
>>> referring to firmware versions, BIOS restrictions, motherboard
>>> support, etc?
>>
>> Yes because it doesn't matter. Unless both sda and sdb are broken.
>
> Once again:
>
> Yes you can configure a particular machine, or a particular detailed
> spec, where this will work.
>
> But I own machines where there is a single boot hard disk setting in
> the BIOS and if that drive fails it is not possible to specify a
> failover device.
>
> It is _not_ possible to make a blanket statement "do this and this will work".
>
> There are hardware setups where it won't. You are not considering that case.
>
> Which is why I said _might_.
>
> There are setups where it _might_ not work, and that kind of thing is
> why people like me write manuals which carefully say "this might work
> but don't rely on it", and why some people use /boot filesystems even
> today, which is the point of this thread.

I'm not saying "might."

I'm saying that I've used an mdraid1 "/boot" as a separate filesystem
or as directory on "/" on at least 100 systems since 10.04 (when grub2
became the Ubuntu default; in those early days, the mdraid support was
flaky) and I haven't had a booting problem when one disk in a mirrored
pair has flaked out.

So, from my practical experience, I can make a blanket statement that
it works just as well as other crucial parts of a system like loading
a kernel, booting a system, or running a network-facing daemon.

You can hit a problem with grub, in the same way that you can hit a
problem with any other part of the software stack. But fretting about
grub being fragile or more fragile than other installed packages is
unreasonable.