Ubuntu: Dell PowerEdge T20 won't reboot


I have a Dell PowerEdge T20 microserver running Ubuntu 16.04. Everything is working fine, except that it won't reboot cleanly.

When I issue run the reboot command, the last messages displayed are similar to these:

    [  OK  ] Reached targed Shutdown.  [ 237137.043209] systemd-shutdown[1]: Failed to initialize DM devices, ignoring  

I've tried adding the following to /etc/default/grub (and running update-grub and rebooting), but it doesn't help:


The BIOS is up to date (version A06).

Can anyone suggest anything else I can try please?


I recommend working through the reboot= options one by one and testing to see if they work rather than trying them all in one go. The reboot= option takes one of these options at a time, rather than multiple options (for those interested, see reboot_setup() in kernel/reboot.c in the kernel source).

So, try: reboot=warm then reboot=cold then reboot=bios etc in /etc/default/grub (and running update-grub and rebooting then testing the reboot).

In my experience, triple faulting the CPU (reboot=triple) will always reboot an Intel processor and reboot=pci should generally always work too.


This implies that there is something wrong on the kernel level, precisely with the device-mapper, and systemd has nothing to do with the error since it shuts down the server fine.

When performing an upcoming reboot; Can you do:

# sync && reboot  

And notice how long does it take to see the error message? Does it take around 120 seconds? Or does it appear instantly?

Can you add the below to the kernel parameters, and check what systemd says after a reboot?

systemd.log_level=debug systemd-log_target=kmsg log_buf_len=1M enforcing=0  

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