"Cascade" of camera failures

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dillius
Posts: 4
Joined: Sat Jun 22, 2019 2:21 am

"Cascade" of camera failures

Post by dillius » Sun Jun 30, 2019 7:00 pm

I have been running a Zoneminder setup for about 2 years now, initially with 4 cameras on it (mostly Wansviews) now up to 7.

I recently updated to 1.32.x and have been struggling with a number of issues, but recently noticed something very odd that I'm trying to give more though to and gather more information on.

My cameras failures seem to "cascade"; when one of them is having connectivity issues, it will then propagate to other cameras causing more failures in the ZMC processes. These are characterized by Errors stating that the mapping file size did not match the expected, which seems to cause the ZMC processes to restart and attempt to reconnect?

This is typically caused by a particular camera that I received that frequently needs to be power cycled to recover that I haven't diagnosed yet.

Obvious thoughts:

1. Does my wireless just suck?
This was my prevailing concern for a long time, particularly after tweaking the performance a great deal in 1.30. However, if I take the problem camera, disable it fulling in ZM, all 6 other cameras work without issue. The first time I figured this out I actually had all 6 other cameras run without any errors for almost a solid week, which has never happened in my history of running ZM.

2. Perhaps this is a symptom of whatever is wrong with that one camera?
Until today I would have believed that, but I had to rearrange some furniture/equipment which affected the signal of yet another camera. Once this one failed to connect, I began to witness the cascade effect yet again.

3. Is it the performance of the box?
It is certainly a weak machine I'm running ZM on, however the temp file system is less than half full at any time; I am nowhere near using all of my available memory (all cameras are tweaked to 2FPS running at 720p). CPU usage rarely peaks above even 40% and the Load is below 1.0 unless I'm running a Montage. I also have all cameras capped in ZM at 3fps max, so that the disconnection doesn't cause runaway CPU usage.

4. Cheap cameras are the problem?
It may indeed be the Wansview W3, which are 6 of my 7 cameras. However, even during these issues, the cameras zoneminder is unable to get back connected to respond via their own interfaces and appear to be fine.


Has anyone else witnessed something like this? I'm open to any ideas on what to look at next or what to try to diagnose.

Thanks for any help/advice!

EDIT: Added #4.

foxtrot1014
Posts: 17
Joined: Sun Sep 10, 2017 8:12 pm

Re: "Cascade" of camera failures

Post by foxtrot1014 » Sun Jul 14, 2019 3:55 am

Normally, I don't answer too many questions here because I don't have anything to input. This case is different.

Based on my own experiences (not with wireless cameras, but with wireless in general, both WiFi and other radio technologies) and what you say specifically in 1 and 2, I would take a look at your wireless. And I'd start by taking a look at signal strengths--does strength correlate to failure order, is the camera with the weakest signal the first to fail? Take a look in your access points interface, there should be a way to see signal strengths.
There's a chance that the bandwidth going through your access point(s) is stressing a component in it, which could cause a degradation in its ability to receive weaker signals. A feedback loop can then be initiated as your access point begins doing extra work trying to handle gradually shoddier connections.

It being a wireless issue is maybe not the most likely problem, but it's pretty unobtrusive and easy one to check in on. Check for a potential correlation between strength and failure. If you further suspect that this IS the problem, the next step would be to move one or more of the cameras closer to the access point, or try shutting down some of the cameras, or try connecting some of the cameras to a different access point.

(you can pick up a Linksys (Cisco) WRT54G wireless router at goodwill for a few dollars--they're great for testing wireless things and even make a pretty decent access point if you leave all your bandwidth-heavy networking (like cameras and home theater) to wired connections)

dillius
Posts: 4
Joined: Sat Jun 22, 2019 2:21 am

Re: "Cascade" of camera failures

Post by dillius » Mon Jul 15, 2019 1:37 am

Thanks for the input.

It definitely is the one with the weakest wireless signal that dies first, though most of the ones that are "cascaded to" have 90-100% signal rating in the camera's own interface.

I currently have 3 different routers, one acting as the true "router" and the other two acting as access points.

I have incidentally run into something that may be an issue; I was trying to get zmNinja to work and found out that my Zoneminder was still running under PHP5 instead of PHP7. I just figured this out yesterday, but its looking like fixing that is having an impact. Will report here in a week or so if it continues to improve.

foxtrot1014
Posts: 17
Joined: Sun Sep 10, 2017 8:12 pm

Re: "Cascade" of camera failures

Post by foxtrot1014 » Mon Jul 15, 2019 10:40 pm

Sounds like PHP versions frequently cause issues. This wasn't the right solution for a problem I was having, but it was a suggestion:
bbunge wrote:
Sun Jul 14, 2019 12:39 am
Likely in doing the upgrade to Bionic you ended up with two versions of PHP. Bionic uses PHP 7.2 so you need to uninstall the older version.

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