Benefits
Benefits
Posted Jun 11, 2023 11:07 UTC (Sun) by anselm (subscriber, #2796)In reply to: Benefits by jccleaver
Parent article: Seeking the endgame for Debian's /usr merge
The main observation here is that once you've done the /usr merge, there are various advantages that result from this, but the main argument against it seems to be “it's not what we're used to, and we don't like it”. (Now where have we heard that before?) It's also not really a systemd thing; systemd doesn't care whether a system has been /usr-merged or not.
Why should the structure of today's systems be beholden to the fact that 50 years ago some guys couldn't fit all of their software on one hard disk?
Posted Jun 18, 2023 18:55 UTC (Sun)
by birdie (guest, #114905)
[Link] (3 responses)
Exactly.
I wonder what benefits the original divided system had. I cannot think of any. Yeah, 30 year ago or so /usr was too big and /bin /lib /sbin were necessary to boot the system. We've long migrated to initrd which made this division redundant. Modern disk are crazy spacious, so again this division is redundant.
Posted Jun 19, 2023 9:25 UTC (Mon)
by geert (subscriber, #98403)
[Link] (1 responses)
Posted Jun 19, 2023 12:57 UTC (Mon)
by anselm (subscriber, #2796)
[Link]
Yes, but all of these also apply to a post-/usr-merge system.
The root/usr split is an accident of history that is now finally getting fixed for good (in Debian GNU/Linux, anyway – as with. e.g., the init system, most other Unix-like systems including many other Linux distributions have addressed this ages ago). There's really no more to be said other than let's get it over with already.
Posted Jun 19, 2023 13:45 UTC (Mon)
by farnz (subscriber, #17727)
[Link]
Having the root directory be completely ephemeral (could be a tmpfs set up by the initramfs) is useful, because it makes it trivial to do quite major surgery on your installation.
If you have the virtual filesystems (/proc, /dev, /sys etc), a /tmp for "temporary files, may be deleted any time", a /system (could be named /usr) for the installed system, and a /user-data (could be named /home) for user data, you now have some nice properties. First, you can unmount the user data at any time, in order to protect it somewhat from mistakes. Second, you can do things like take a snapshot of the current system area, do major surgery (e.g. try to convert in place from x86-32 to x86-64), and just roll back cleanly if your major surgery goes wrong. Thirdly, you now don't treat any partition specially in a rescue situation - because / is an ephemeral tmpfs, you just create one, mount in all the FSes, and now you have your rescue layout to examine.
With 20/20 hindsight, putting things directly on the root FS was a bad decision. But it's often better to make a bad decision and get something working than to never get anything to run at all for fear of making a mistake.
Benefits
Benefits
- less chance of it becoming corrupted, either due to manual errors or due to bugs,
- no need to wait for fsck to finish checking your huge /usr file system on every boot.
- You can share/clone /usr among multiple machines (compared to /var, which is machine-specific).
Benefits
Benefits