[OpenIndiana-discuss] Problems with some zfs fs unable to mount after shutdown

[Toomas Soome]

> On 14. Jan 2022, at 06:32, hput via openindiana-discuss <openindiana-discuss at openindiana.org> wrote:
> 
> Flemming Dalsgaard <flemming.dalsgaard at gmail.com> writes:
> 
>> The commands
>> zfs create -omountpoint=/export            p0/export
>> zfs create -omountpoint=/export/home       p0/export/home
>> zfs create -omountpoint=/export/home/USER  p0/export/home/USER
>> 
>> Should be sufficient to make the /export/home/USER
>> so you should not pre create the involved folders, zfs take care of that it
>> self.
> 
> [...]
> 
> exactly what I did, and I did not precreate anything.  Not sure where
> that came from. I just ran the zfs create commands and it all mounted
> as expected.... And once again following this mornings boot up of host
> and then vm in question...
> 
>>> zfs create -omountpoint=/export            p0/export
>>> zfs create -omountpoint=/export/home       p0/export/home
>>> zfs create -omountpoint=/export/home/USER  p0/export/home/USER
> 
> 
> It fails to mount those filesystems and drops into a console login on
> reboot.
> 
> I needed a reboot for host OS due to certain updates that apparently
> need a reboot.  And then booting the oi vm
> 
> <oi-failed-mount_220113.png>
> I login as root and run:
> 
> zfs mount p0/export
> zfs mount p0/export/home
> zfs mount p0/export/home/reader
> 
> And they all mount fine.
> 
> But yet I'm stuck with a console to work in ... pretty sure if I
> reboot the vm the same thing will happen.
> It seem the OS doesn't mount them from the bottom up or something
> What is causing the failure?
> 
> Attempting to `startx' from console does not work at first but finally
> produces a very primitive X desktop, that near as I can tell is less
> usable for work than the OI console (which is saying something) 
> 
> How can I go into X from the console login.. Logging out does nothing.
> Apparently the only recourse is to reboot the vm again.  Doing that
> now:
> 
> First thing, I see `unable to read pool p0' as the shutdown starts to
> happen.  But, glory be.  With another 12-14 minutes lost to the ether,
> The bootup completed and didn't fail to mount p0/export/home/reader
> 

First thing to remember - command ‘zfs mount’ will fail if mountpoint is not empty. This means, if you add new storage for /export, you need to make sure the original is not present (rpool/export dataset).

Also, make sure you are not creating cross mounts from different pools/datasets.

And finally, a small nit - if you create /export/home/username tree, your dataset tree should look like <pool>/export/home/username, and this means, you only need to set mountpoint for<pool>/export, rest will follow the hierarchy. This can help to avoid cross mounts and populated mount points…

rgds,
toomas