Re: support for merged /usr in Debian
On Mon, 04 Jan 2016 12:01:46 +0100, Ansgar Burchardt
>Marc Haber <email@example.com> writes:
>> On Sun, 03 Jan 2016 13:28:14 -0800, Russ Allbery <firstname.lastname@example.org>
>>>But I don't get why people who are using non-embedded UNIX systems
>> I, for example, am afraid of having to merge /usr in existing systems
>> during upgrades, causing repartitions to be necessary. I am afraid of
>> partition layout suddenly not fitting any more during an upgrade,
>> causing downtimes and customers considering to take the opportunity to
>> migrate to a really supported enterprise distribution.
>Are you afraid of your /usr partition being too small to hold the
>additional binaries from /bin, /sbin and /lib? If that is the case,
>won't it also be too small for regular distribution upgrades?
I don't know yet.
>Remember that / and /usr don't have to reside on the same partition with
>the usrmerge proposal: they only have to be both available
>post-initramfs. The initramfs already takes care to mount /usr (for the
>systemd case as initscripts needs updates for sysvinit as was said
>elsewhere). So no repartitioning should be required on upgrades.
I'd like to have a positive confirmation that systemd upstream intends
to continue supporting this scheme and that Debian will also.
Otherwise, there is always the possiblity that systemd upstream will
condemn our setup "broken" and goes out to "educate" us how to
"properly" run a "modern" Linux system by removing support for things
that have always worked in the past.
>> And, I really don't want to have to adapt, test and verify scripts and
>> backup schemes to changed partition layout. This will be necessary for
>> new systems, and it is really a horror vision to have to do this for
>> existing systems during upgrades.
>I wouldn't expect much changes to be needed for backups: if you excluded
>/bin, /sbin, /lib and /usr, then it would be enough to just exclude /usr
>in the future. If you included them, they will still be included.
Think some backup system that backs up every file system by its own
and runs with directives to stay on the file system. There is ample
possibility to error out when a backed-up file system suddenly goes
out of existence with an upgrade, or that some part of the file system
is inadvertently excluded from the backup when the file system layout
is severely "modernized" during a system upgrade.
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