How I solved “E” status on a RAID0 volume for a Synology DS411

I recently had a problem with my Synology DS411 NAS and spend quite some time to solve it as information about this is quite sparse.

In the middle on the night (sigh), my DS411 started to beep because of an hard drive failure. It woke me up… I switched it off, thinking that I would disable ALL beeps and alarms in the morning so it won’t happen again !

In the morning, I restarted it. And although I was using a RAID0 array with 2 disks, I did not loose any data as the RAID0 array was still available but mounted as Read Only. I did a backup of data I needed… just in case the disk would really fail…

Looking at disks logs in DSM, it showed 11 write errors. Running a S.M.A.R.T. test from DSM did not report any issue. I then stopped the NAS, extracted the faulty disk, connected it to a PC and ran vendor’s test utility (full test) and also a full test using a very nice tool called Spinrite. No error whatsoever.

It seems that one of the two disks encountered a transient read / write error and that Synology software, for the sake of the data, decided to set an alarm and protect the volume, mounting it as Read Only. Which is, I believe, a very good thing.

This is where it becomes tricky : having the disk thouroughly checked, how to reset the alarm and remount the volume in Read Write mode ? Nothing found on Synology web sites, forums or on the web…

I finally opened a case at Synology who has been quite helpless… They made me reinstall DSM because I was using non official package source although it was obvioulsy an hardware problem. But they finally, at least, put me on the track of solving the problem.

The solution I found and describe here worked for me. But it may not for you. Unless you know what you are doing, have proper backup or are ready to loose all data on the disk, don’t apply that. I can’t be held responsible for the loss of data.

I connected to the NAS through SSH and ran the following :

Digging a bit more, I discovered that the “E” status in [UE] is very specific to Synology and hence not documented in standard documentation… but neither in Synology documentation ! As you guessed, it means Error.

So now, how to reset it ? And that is where Synology have been helpless… they did not immediately pinpoint the problem and gave me the solution although it is Synology specific and they rather told me to reinstall DSM and that they were not providing Linux support…

I did something… scary… But I did backup important files before. So, again, if this worked for me and not for you, don’t blame me !

I stopped the RAID volume and recreated it (using guidance from here.)  Obviously, the values in the command line need to be adapted to your context.

Just answer yes when it asked for confirmation because disks are already part on an array.

And TA DA !

The –create option “just” writes the configuration of the array, leaving all data intact. After, you can reboot or mount the volume manualy.

And all the data is there !

Hope it will help !

2 thoughts on “How I solved “E” status on a RAID0 volume for a Synology DS411

  1. This post has helped me so much. I am using XPenology on VMware and one of my VMware (VMDK) disks crashed?!?!. I have followed your solution and have reset the [E] status and now everything works perfect. Before your solution however, i ran the e2fsck -y -v /dev/.
    Thanks again.!

    • Hello Paschal,
      Thanks a lot for your kind feedback. I’m always glad to know one of my posts helped 🙂
      Also, it is interresting to know it worked with XPenology which I did not know about by the way.
      Jean-Sébastien

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