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 !

NetAtmo : now they have a connected thermostat !

netatmo3NetAtmo is a french company now well known for its connected weather station.But not only ! They now have also a connected thermostat so you can control your home heating from internet, using their own app or the provided API.

Much like Nest thermostat (but far less expensive…), it can “learn” from you behavior and just stop and start heaters when needed.

Nice… I think I will replace my “old”, not connected & closed Delta Dore thermostat !

Discovering openHAB

I was looking for a software I could use to build a neat remote control for home automation on iPhone and Android tablet.


I first found OpenRemote which is quite nice. I already used it to build a remote for my IP remote controlled power strip.

But OpenRemote it did not work really as I expected (may be a bit complex to use) and the OpenSource version seems not to be really active on the development side.


So I did look around to find an atlernative and finally discovered openHAB quite a while ago. When I first discovered this project, current version was 1.2.

Since then, the latest release is 1.4 and they have a very nice new website.And, most importantly, they build which allows managing your hosted HAB instance from the Web (currently in beta).

With openHAB, you can build simple interface for the Web, iPhone, iPad, or Android devices. It is probably not as powerfull as OpenRemote but then is quite a few “bindings” for many devices or protocols (http, tcp, ntp, Google calendar, EnOcean, KNX…) More than 50 are available today.

With a few lines of code, you can build a nice interface to your home automation systems…

… on iPhone


… or Android !



Nice !