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Forum Discussion
Volume Readonly after blackout
Although I have my Ultra 6 Plus connected to an UPS that is supposed to shut it down once a critical level of battery is reached, a few days ago while a blackout the NAS eventually was taken down abruptly. As the power from the city was coming back and off for a couple of hours, the UPS signaled the NAS to start again at a point where there was very little battery power to allow for an ordenered shutdown.
After power was finally restored, and the NAS restarted initially I noticed nothing wrong, however, yesterday I noticed the apps (Emby and Plex) installed on the NAS were not working. I tried to manually restart them but found their databases were corrupted. So I decided to uninstall and reinstall them. Nothing seemed out of the ordinary until I noticed that trying to reinstall the apps were failing.
Once I went into the admin console, I noticed the Volume was in Read Only Mode. and when looking at the log I noticed some entries en the dmseg log stating:
BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727
I ran a Disk Test on the NAS for the 6 bays it has and no error was reported. The data seems fine and available but the volume is in readyonly mode. Not sure how to fix this, restarting the NAS does not cause the volume to be mounted normally.
Not sure where to go from here... of course, paid support on this model is not an option. I am running OS 6.10.3 without issues for quite some time until this blackout ended up with a unclean shutdown.
Any hints on how to solve this?
15 Replies
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Smaky wrote:
Once I went into the admin console, I noticed the Volume was in Read Only Mode. and when looking at the log I noticed some entries en the dmseg log stating:
BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727
md126 is the data volume, and those errors is why the volume is read-only.
The first thing to do is to back up your files.
The safest way is to switch to flexraid, destroy the volume, recreate it, and then switch back. You'll then need to recreate the shares, reload the data and reinstall the apps.
You could alternatively try btrfs check -repair - which is risky, so it is important to make the backup before you try it.
Thanks for your reply. I am now doing a full backup of the data. Fortunately so far it has been progresssing without issues. Once I am done, I'll try to repair first.
I noticed the btrfs check command (without repair) shows the volume is online. Can md126 volume be unmounted? Looking at the log, there are not too many btrfs errors and all of them related to single block:
[Mon Jun 1 00:16:19 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:19 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:19 2020] BTRFS: error (device md126) in balance_level:1912: errno=-5 IO failure [Mon Jun 1 00:16:19 2020] BTRFS info (device md126): forced readonly [Mon Jun 1 00:16:20 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:20 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:20 2020] BTRFS: error (device md126) in balance_level:1912: errno=-5 IO failure [Mon Jun 1 00:16:20 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:20 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:20 2020] BTRFS: error (device md126) in balance_level:1912: errno=-5 IO failure [Mon Jun 1 00:16:20 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:20 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:20 2020] BTRFS: error (device md126) in balance_level:1912: errno=-5 IO failure [Mon Jun 1 00:16:20 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:20 2020] BTRFS critical (device md126): corrupt leaf, bad key order: block=14964045447168, root=1, slot=727 [Mon Jun 1 00:16:20 2020] BTRFS: error (device md126) in balance_level:1912: errno=-5 IO failure
Smaky wrote:
I noticed the btrfs check command (without repair) shows the volume is online. Can md126 volume be unmounted?
You could try umount /data.
If that fails,then you'd need to boot up in tech support mode, chroot, and then run the command.
Has your NAS ever been vertically expanded (i.e., is there an md127 that is also part of the volume)?
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