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Guide

Jan 13, 2020

Solved

RN214 on 6.10.2: The volume data encountered an error and was made read-only.

This past weekend, my ReadyNAS gave the following error:

The volume data encountered an error and was made read-only. It is recommended to backup your data.

There's no indication what the actual error / issue is, only that there is an error, and my device is now read-only.

I have:

Rebooted multiple times
Run Disk Check (everything passed)
Reviewed the Logs (no further errors or details are seen in them)
Run smartctl (long) on all 4 drives, all drives passed, no errors are present

At this point, I believe the issue to be software / file system related. I do have multiple backups already (learned that one the hard way a few years ago), so that's not a worry. Before I nuke it and restore, which would be a pain, is there any way to:

Find out what caused this, to prevent the issue from re-occuring
Potentially fix it using a check / command, or a replacement part if it turns out it's hardware

I am an IT System Engineer for a living, so while I am comfortable doing most operations, I also want to know why an issue occured (root cause of failure), so I know how to prevent it / fix it in the future.

I have device logs and the smartctl results all downloaded and available, if needed.

Thank you for your help!

Marc_V
Jan 13, 2020
GJSchaller

Those BTRFS errors might be able to fixed on the backend but it would be best if you start over. Cause of this errors might be due to dirty reboots that caused transactions to not complete. Not really sure how to explain but if you have any chances of outages or power loss or disk failures while in use then that can contribute.

HTH

Regards

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Marc_V
NETGEAR Employee Retired
Jan 13, 2020
GJSchaller

Have you checked status.log or volume.log for any warnings or information on Root OS volume or Data volume has been consumed to 100%? You may also want to check dmesg.log for any kernel or btrfs errors.

If there are FS errors, I would suggest doing a Factory reset if possible.

HTH

Regards
- StephenB
  Guru - Experienced User
  Jan 13, 2020
  In addition to dmesg, you can look directly in system.log and kernel.log for disk and btrfs errors. Maybe also look at disk health (disk_info.log).
  
  If you want to see OS partition fullness, scroll down to the end of volume.log at the df section. The OS partition is /dev/md0.
  
  FWIW, several folks here have found that when they rebooted with a read-only volume that the volume didn't mount. That hasn't happened to you yet, but I wouldn't count on that continuing.
- GJSchaller
  Guide
  Jan 13, 2020
  Status.log, volume.log both look good.
  
  dmesg.log has some warnings about my Ethernet - I did just switch how the device is connected to my network, but I didn't think that would impact the file system.... to be safe, I'll revert those changes and be sure.
  
  As noted, I do have a backup, I just hate resetting a device without having an understanting of what failed and why.
  - GJSchaller
    Guide
    Jan 13, 2020
    OK, now we're getting somewhere.... found this in dmesg.log:
    
    [Sun Jan 12 17:18:29 2020] BTRFS error (device md127): parent transid verify failed on 7765871394816 wanted 4157903 found 4225465 [Sun Jan 12 17:18:29 2020] BTRFS error (device md127): parent transid verify failed on 7765871394816 wanted 4157903 found 4225465 [Sun Jan 12 17:18:29 2020] BTRFS warning (device md127): Skipping commit of aborted transaction. [Sun Jan 12 17:18:29 2020] BTRFS: error (device md127) in cleanup_transaction:1864: errno=-5 IO failure [Sun Jan 12 17:18:29 2020] BTRFS info (device md127): forced readonly [Sun Jan 12 17:18:29 2020] BTRFS: error (device md127) in btrfs_drop_snapshot:9412: errno=-5 IO failure [Sun Jan 12 17:18:29 2020] BTRFS error (device md127): could not do orphan cleanup -30 [Sun Jan 12 17:18:29 2020] BTRFS info (device md127): delayed_refs has NO entry