Re: Hooks for automount

[Ed Greshko]

On 10/03/2021 20:57, Patrick O'Callaghan wrote:
> [Sorry for the long delay, but other stuff intervened.]
>
> I've come back to this now and started experimenting incrementally. As
> a first step, I just want to automount/unmount, ignoring the power-
> on/off part for now, i.e. the device is already powered on. This is my
> /etc/fstab entry:
> UUID=6cb66da2-147a-4f3c-a513-36f6164ab581       /raid                   ext4    rw,noauto,user,x-systemd.automount 0 0
>
> and /etc/systemd/system/raid.automount (copied from your example):
> [Unit]
> Description=Automount /raid
>
> [Automount]
> Where=/raid
> TimeoutIdleSec=10
>
> [Install]
> WantedBy=multi-user.target
>
> I've rebooted, and the device starts up mounted:
> # findmnt /raid
> TARGET SOURCE    FSTYPE OPTIONS
> /raid  systemd-1 autofs rw,relatime,fd=52,pgrp=1,timeout=10,minproto=5,maxproto=5,direct,pipe_ino=24910
>
> though I'm not sure why as nothing is accessing it. It also remains mounted, despite the timeout.
>
> Any thoughts?

My first thought is that you're doing things a bit different than what I did.

You have an entry for your disk in the fstab.  My understanding is that when an entry is in fstab mount unit
files will be auto generated.  I don't have fstab entries for my automounts.  I can't say that I know it is wise
to mix the methods.

Using my /aux as the example.  When unmounted I see...

[root@meimei ~]# findmnt /aux
TARGET SOURCE    FSTYPE OPTIONS
/aux   systemd-1 autofs rw,relatime,fd=53,pgrp=1,timeout=60,minproto=5,maxproto=5,direct,pipe_ino=26036

But when mounted

[root@meimei ~]# findmnt /aux
TARGET SOURCE           FSTYPE OPTIONS
/aux   systemd-1        autofs rw,relatime,fd=53,pgrp=1,timeout=60,minproto=5,maxproto=5,direct,pipe_ino=26036
/aux   nas:/volume1/aux nfs4 rw,relatime,vers=4.1,rsize=131072,wsize=131072,namlen=255,soft,proto=tcp6,timeo=600

I think I would first try removing (commenting out) the fstab entry and creating raid.mount file in /etc/systemd/system/
with the contents.

[Unit]
Description=mount raid

[Mount]

What=/dev/disk/by-uuid/6cb66da2-147a-4f3c-a513-36f6164ab581

Where=/raid
Options=rw,user
Type=ext4

[Install]
WantedBy=multi-user.target

At this time I've only used automounts for nfs mounts.  I'd try it with local disk if it weren't for the late hour.

Also, due to the late hour, I seem to recall seeing something about working with automounts and external devices
and conflicts arising due to the interference of udev.  But I may be mixing things.  So, I'd first see if making the
above changes has any effect.