On 03/01/16 23:18, Ben Hutchings wrote: >> Then why is it that since the introduction of systemd is having /usr on >> a separate partition suddenly considered evil and systemd complains >> loudly about it. It always has worked and does work fine for me with >> sysvinit > > systemd complains if it has to mount /usr itself. This is because > mounting of local filesystems generally depends on various services and > udev hooks that may themselves depend on /usr. This is also true when > using sysvinit. Some services go through contortions to work before > /usr is mounted; others may behave subtly differently if it's a > separate filesystem. We really need a simplified code path for > mounting /usr early on, and that is now provided by the initramfs. Ah, so it's actually packages that don't separate device configuration logic from the application or daemons properly that has caused the brokenness. Can we identify and fix the packages that cause this issue? Is this also something to do with the inherent lack of determinism and parallelization in systemd's startup as well (just out of interest)? Having to do all this contortionism and particularly mounting /usr in initramfs sounds like a horribly insane way to do things! > >>>> That just means systemd is broken by design and needs to be fixed. >>> >>> If what you claimed were true, then I'd agree with you, but since all >>> the systems I've upgraded to systemd have a separate /usr, and are >>> working without any issue whatsoever, this drivel can be safely ignored. >>> >> Then what's the problem and why are we even having this conversation >> about merged /usr??? > > As I understand it, merging /bin and /lib into /usr allows us to > support certain uses cases more easily - e.g. package installation in a > filesystem transaction, or sharing an NFS /usr filesystem. > Package installation in a filesystem transaction? Is that in relation to btrfs and filesystem versioning to support easy rollbacks? For that you'd need to keep everything except /home and /srv to be able to easily and consistently roll back to a particular state. TBH the only argument I've heard so far that holds some water is the nfs shared /usr and even that seems largely a convenience issue rather then a hard problem. -- Daniel Reurich Centurion Computer Technology (2005) Ltd. 021 797 722
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