Bug#782793: systemd: ext4 filesystem on lvm on raid causes boot to enter emergency shell

[Michael Biebl]

Am 23.04.2015 um 21:47 schrieb Rick Thomas:
> 
> On Apr 23, 2015, at 1:29 AM, Michael Biebl <biebl at debian.org> wrote:
> 
>> There might be a race somewhere, i.e. lvm2-activation(-early).service
>> being run *before* mdadm has assembled the RAID.
>>
>> You could test this theory, be artifically delaying those two services.
>> Copy them to /etc/systemd/system, and add a ExecStartPre=/bin/sleep 30
>> to the [Service] section of those two units.
> 
> 
> So… That worked (adding a 30-second delay) twice in a row.
> 
> Let me know if you want to see a log with debug turned on for such a reboot.
> 

Ok, I guess I have bad news then.
lvm2 in jessie is not really hotplug aware. The
lvm2-activation(-early).service units run at a static, fixed time during
boot. You'd need something like lvm2's lvmetad support [1]. I tried to
enable that in Debian today, but failed miserably due to various bugs
(already filed 3 bugs today regarding lvmetad).
Ultimately, this is something which needs to be fixed in lvm2 and at
this point I don't think there is a lot more that I can do from the
systemd side.

Sorry for the unsatisfying answer.

Regards,
Michael



[1]
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/metadatadaemon.html
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