MinimServer stopped on Synology NAS

[simoncn]

I have tried pulling the network cable on my NAS (a DS115) and it did not reproduce the problem. It would be interesting to know whether it does on your NAS.

[squarefrog]

OK that worked a treat. Steps to reproduce:

1) Stop/start minim to reset logs
2) Pull network cable, and replace
3) Pull network cable and replace again, within 5 seconds

Note, step 3 was required. So I suppose you are pulling the network link while open home is still trying to reinitialise.

I tried without step 3, and once the NAS got its IP address again, minim carried on working.

I'll email you the logs.

[simoncn]

Thanks very much for this. The log provides some important clues. The failure seems to be caused by a combination of events and it will take me some time to analyse what is happening. It doesn't appear to be quite as simple as a race between ohNet reinitialising and pulling the cable.

I followed your instructions but they don't cause a failure on my NAS. What NAS model do you have? If my NAS is faster or slower than yours, I might need to change the timing of the pull and replace operations. If I can reproduce the problem myself, this will make it much easier for me to debug the problem and test a fix.

[squarefrog]

Model is a Synology DS214SE. Let me know if there are any other logs I can gather which will help.

[simoncn]

Despite all efforts I cannot reproduce this failure or the unexplained sequence of adapter removed/added events that I see in the log you sent. This means I can't debug the problem or test any attempted fix. I really appreciate your help but I don't think I can take this any further at the present time.

[Bronx54]

(26-07-2019 22:15)simoncn Wrote:  Despite all efforts I cannot reproduce this failure or the unexplained sequence of adapter removed/added events that I see in the log you sent. This means I can't debug the problem or test any attempted fix. I really appreciate your help but I don't think I can take this any further at the present time.

Thanks for the effort, I will let you know if I find what is causing the issues or changes significantly that may help resolve it. It does look as though it is a hardware issue.

[simoncn]

It could be significant that the only two users who have reported this issue are using a Synology NAS with a Marvell Armada 370 processor.

The Synology firmware behaves in a strange way when the network connection is removed and restored. As well as producing a remove event followed by a restore event, it then produces a number of "phantom" remove/restore sequences. These phantom sequences don't occur on other versions of Linux.

These phantom sequences also occur on my Synology devices and are handled correctly by ohNet. My Synology devices don't have an Armada 370 processor. The log you sent me shows that on your NAS, some events are not happening in the order that they should and I haven't been able to come up with an explanation for how this could happen.

I have previously experienced an unrelated problem that turned out to be caused by a hardware fault in the Armada 370 processor (see this post). This experience has led me to treat this processor with some suspicion when things happen that appear to have no logical explanation. In the case of the other issue, I could reproduce it myself and debug it because I had the necessary hardware to do this and I was then able to implement and test a workaround.

Another possibility is that this isn't caused by the Armada 370 chip but is a timing issue that only occurs with a slow uniprocessor. If anyone reports the problem on another processor, this would eliminate the Armada 370 from suspicion.

Thanks again for all your help with investigating this issue.

[aelkaim]

Hello
I use a Synology 1817+ in France.
It is configured to connect to a VPN (Usenetserver provider)
It has been connected to VPN for a while, but i observed the frequent stops of minim only recently. When i want to turn it "on", i have to launch it twice from the DSM.
I use the last version of Minimserver.
DSM 6.2.1-23824
Regards
Alexandre.

[simoncn]

Which VPN are you using and what are your connection settings?

[aelkaim]

Hello
I'm sorry
I had not seen your answer

My VPN is PPTP
fra-a01.wlvpn.com
AUTH: MS CHAP V2
Cryptage: MPPE 128bits