Every time I boot OMV, my RAID comes back online degraded

    I've been running OMV on my Thecus N5550 successfully for a couple of years now. Only recently whenever I boot the box, my RAID5 setup ends up degraded with a disk (sdb) missing from it's configuration. I can 'fix' it by adding the disk back with mdadm --manage /dev/md0 --add /dev/sdb . Unfortunately it then apparently needs to rebuild, but it will be online again after it's done.


    Of course this is not ideal. What could be the cause?

    I’m not familiar with that hardware, but generally, if the problem is always with the same drive, I would start to look at a bad cable, bad drive, bad sata port, or even something as simple as dirty/tarnished sata contacts, which just reseating the cable a few times on each end can sometimes fix by scraping some of the dirt/tarnish off the contacts.


    I would tackle it by doing binge in this order, stopping when the problem disappears after a reboot.

    First check the SMART status of the drives to see if it is reporting problems.

    Cable reseat (if no cable then a drive caddy reseat several times)

    Cable replacement (if no cable a drive replacement)

    Try the drives in a different system to rule out system hardware problems.


    Just speculation, but if none of that works, and the different system had a fresh omv install, you may even have problems with more than one drive if they are all the same age, but it is the worst one hat is getting kicked from the array because it can’t automatically sync with the others.


    I would suspect bad/dirty contacts, bad cable, or a single bad drive as the most likely suspects though.

    But as long as the box is up it functions just fine, for months on end. Only when I reboot, and every time I reboot, the drive goes missing from the raid config, but is still detected fine in the system, has no issues according to SMART and can be added back without issue.


    I was thinking its more likely it has something to do with the raid config being loaded incorrectly upon boot, but I don't know enough about how that works to troubleshoot it. Is this a possibility and if so how can I check this?


    PS now I've come think of it... The drive that keeps dropping from the raid is currently sdb after a reformat a while back. When it was still working fine it was still sdb2 (partitioned drive then, now using the entire drive). Maybe it's still looking for sdb2 when reassembling the raid?

    Might have found the cause, could indeed be related to me using the entire drive instead of a partition... Weird issue, not very well known...


    the third answer on this page states:


    So, if you create RAID using the whole device (say, /dev/sda, /dev/sdb, ... instead of on /dev/sda1, /dev/sdb1, ...) the RAID device doesn't reassemble after a reboot even if you have configuration saved under mdadm.conf. There is also a possibility of mainboard firmware overwriting or removing the RAID superblock. In my setup, running mdadm --assemble --scan --verbose doesn't get me back my RAID setup and it seems to be the case of RAID superblock not being available.

    Zitat von hapklaar

    Might have found the cause, could indeed be related to me using the entire drive instead of a partition... Weird issue, not very well known...


    the third answer on this page states:


    So, if you create RAID using the whole device (say, /dev/sda, /dev/sdb, ... instead of on /dev/sda1, /dev/sdb1, ...) the RAID device doesn't reassemble after a reboot even if you have configuration saved under mdadm.conf. There is also a possibility of mainboard firmware overwriting or removing the RAID superblock. In my setup, running mdadm --assemble --scan --verbose doesn't get me back my RAID setup and it seems to be the case of RAID superblock not being available.

    Can't confirm this.

    From the beginning I used the whole device and not partitions for my raid, and never experienced an issue like this ...

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