Bug#783321: systemd opens file in /var/run and not in /run

[Simon McVittie]

On 26/04/15 13:12, Dmitry Katsubo wrote:
> Indeed other files could be opened from /var, but in single mode that
> is very limited. The only service that lock it is NFS mount (rpcbind).
> And I can always stop these services, thus allowing me to unmount
> /var. But that is not the case with process with PID=1.

If you're booting into single-user mode to do sufficiently low-level
filesystem surgery that you want /var not mounted, I would really
recommend doing it from the initramfs or a live-CD/live-USB/etc.
environment, not the running system. jessie's initramfs-tools puts fsck
in the initramfs.

In particular, if you suspect that there might be disk corruption, using
the maybe-corrupted system to repair itself seems much less than ideal:
the "critical path" here has quite a lot of files in it (fsck, libc,
ld.so, bash, e2fslibs...)

For the initramfs, only two files need to be intact (the kernel and the
initramfs), and AIUI both of those are compressed data with a built-in
checksum, so if it boots at all, you can be reasonably confident that
it's good.

If you would like a more elaborate recovery environment, I usually go
for a small secondary installation of Debian stable in its own partition
at the end of the disk, but grml and Debian Live are also good choices.

    S