What is causing some cameras to have "no signal"?

[Rockford622]

I have a mixture of Hikvision and Dahua cameras connected to a Dlink 24 port POE network switch. Some of the cameras record to an internal WD Purple 6TB drive and some record to an internal WD Purple 2TB drive. I just updated BI yesterday and all of the "no signals" were at 0, now this is how they are just 24 hours later according to the attached image. As you can see some, have many no signals and some have 0. As you can see from the other attachment, I will get a large grouping of cameras that all seem to have a no signal at the same time, so that would suggest it's not the camera or wiring, etc.

I really have no idea what is causing this because not all cameras are affected. They all have a 20 MB buffer according to BI, btw.

Thanks for any suggestions.

 

[venture996]

I had this issue off and on for 2 years, and thought it was a BI issue. Turned out that a Netgear router that I was using in Access Point mode was doing some bad stuff (I think DHCP related) and when I put it back into Router mode, turned off DHCP, and moved Internet into a LAN port it went away. Not sure what your infrastructure is, but if its similar that's something to look at. I tracked it down when I noticed that rebooting that "access point" would trigger cameras into No Signal on BI.

 

[Rockford622]

So far, it may be a hard drive issue. Last time this happened, I believe BI was in the process of moving files from my local hard drive to my NAS for archiving purposes. While that is happening, there is still lots of data being written to the drive as I record continuously.

Perhaps "no signal" is Blue Iris's way of saying the buffer ran out. Still have more testing and observation to do.

Thanks for the response.