[systemd-devel] more verbose debug info than systemd.log_level=debug?

[Holger Kiehl]

On Sat, 8 Apr 2017, Chris Murphy wrote:

> On Tue, Apr 4, 2017 at 11:55 AM, Andrei Borzenkov <arvidjaar at gmail.com> wrote:
> > grub2 is not limited to 640KiB. Actually it will actively avoid using
> > low memory. It switches to protected mode as the very first thing and
> > can use up to 4GiB (and even this probably can be lifted on 64 bit
> > platform). The real problem is the fact that grub is read-only so every
> > time you access file on journaled partition it will need to replay
> > journal again from scratch. This will likely be painfully slow (I
> > remember that grub legacy on reiser needed couple of minutes to read
> > kernel and much more to read initrd, and that was when both were smaller
> > than now).
> 
> OK well that makes more sense; but yeah it still sounds like journal
> replay is a non-starter. The entire fs metadata would have to be read
> into memory and create something like a RAM based rw snapshot which is
> backed by the ro disk version as origin, and then play the log against
> the RAM snapshot. That could be faster than constantly replaying the
> journal from scratch for each file access. But still - sounds overly
> complicated.
> 
> I think this qualifies as "Doctor, it hurt when I do this." And the
> doctor says, "So don't do that." And I'm referring to Plymouth
> exempting itself from kill while also not running from initramfs. So
> I'll kindly make the case with Plymouth folks to stop pressing this
> particular hurt me button.
> 
> But hey, pretty cool bug. Not often is it the case you find such an
> old bug so easily reproducible but near as I can tell only one person
> was hitting it until I tried to reproduce it.
> 
I too was hit by this bug on one of my systems. But what I did is that
I just removed all plymouth rpms and everything was good form that moment
on.

Holger