Re: usr-merge, was Re: Back to systemd [was: Re: New list for Raspbian? (was: Re: systemdq)]
On Fri 03 Jan 2020 at 21:13:42 (-0500), Kenneth Parker wrote:
> On Thu, Jan 2, 2020 at 12:51 PM David Wright <deblis@lionunicorn.co.uk> wrote:
> > On Thu 02 Jan 2020 at 06:04:03 (-0500), Steve Litt wrote that usr-merge
> > causes problems with systems that are initramfs-free (and /usr is a
> > mounted filesystem). I don't think Debian has supported such systems
> > in a long while, so you're really on your own with creating and
> > booting those.
> >
>
> I'm glad I found this out! I have a Jessie System with a VERY small Root
> (2G), and separate /usr and /home Partitions on a different Hard Drive.
Yes, but are you booting conventionally using an initramfs (ironically
with the filename initrd…), or are you, like Steve Litt, avoiding any
use of initramfs? Only the latter should cause you any bother.
For someone booting with an initramfs, the effect of usr-merge is to
move all the files in /bin, /sbin and /lib into /usr, which means that
your root partition will be a little emptier. On this laptop's
previous installation of stretch, that would save
9.9M /wrens/bin
10M /wrens/sbin
496M /wrens/lib
4.0K /wrens/lib64
from the root partition. (/wrens is the mountpoint of my old stretch's
root directory.)
> I suspect that Buster wouldn't install well on this at all! :-)
There's no disadvantage in having a separate /usr partition in Buster;
in fact, it can be an advantage as you can mount it readonly because
none of the files is written to (except when installing software, of
course). I used to do this when I ran systems with multiple users
connected to the Internet with no firewall. With usr-merge, your /bin,
/sbin and /lib would also benefit from being in the readonly partition,
rather than in the read-write / partition.
When you boot, all the files that are required, which were once in
/bin and /sbin, are nowadays in the initramfs. (A lot of them are
actually bundled up in /bin/busybox, which has almost 250 hard
links in my initramfs.)
> Thanks for the info. I enjoyed reading Bug Report 914897.
Cheers,
David.
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