[systemd-devel] crypttab automount

[Ralf Jung]

Hi,

> You were looking for the "noauto" option for crypttab (it's in the manpage,
> btw).
> The unit will then only get activated when the automount point is accessed.
> As far
> as I know, this will only work if the corresponding fstab device is from
> /dev/mapper/.

Oh, wow. I wonder how I missed that one. Thanks a lot!
"systemctl show" still shows the cryptsetup service "Before"
cryptsetup.target, but it doesn't seem to be pulled in by anything
anymore, so this ordering requirement is not a problem (is that correct?).

Speaking of noauto, I have both noauto and the automount option in
/etc/fstab for this device. According to the documentation, noauto means
no dependency is added to local-fs.target, but it seems that in
combination with automount, that dependency *is* added nevertheless, but
it points to the automount unit instead of the mount unit. Did I
misunderstand something? If not, I think the documentation should be
clarified here. Something like

  With noauto, this mount will not be added as a dependency for local-
  fs.target. This means that it will not be mounted automatically
  during boot, unless it is pulled in by some other unit. Option auto
  has the opposite meaning and is the default.
> If an automount unit will be created for this file system, noauto has
  no effect. <


Now I just have to figure how to make this mount happen automatically at
boot, but without the login prompt waiting for it. I don't want the
first access to /mnt/store to take ~1.5 seconds - that just moves
waiting time from boot to later, which makes no sense. There's enough
spare time in between where the machine could do this.
However, I think that if I (somehow) tell multi-user.target to "Want"
mnt-store.mount, then the "Before" that's still in there will mean that
boot will wait again (if I understood this Want/Requires vs.
Before/After business properly).
Essentially, I want a proper mount with the usual RequiredBy and
WantedBy - but without the Before that makes others wait on this disk.
So, the concurrency part of automount is exactly what I want, but
without the on-demand part. Is that possible?

Kind regards
Ralf