Help. Restarted NAS and now as soon as I start ZoneMinder /dev/shm shoots to 100%

[Hendergd]

Help
I've zoneminder running on my synology DS218+ in a docker container and it has worked flawlessly for ages now. I run half a dozen cameras at 5fps and it just works. Today I shutdown the NAS to fit a UPS and when I fired it all up again I can't get zoneminder working. The containers starts without error and the zm web interface is there and zmNinja can connect and see past events but none of the cameras are capturing nor can I monitor them. The camera's rtsp feeds are fine and I can see them in vlc but zoneminder just sits there. /dev/shm: is red and at 100%
If I disable all cameras in the zm interface and restart /dev/shm goes to zero% but as soon as I start even one feed it's back at 100% again

Can anyone help. I've changed nothing and the NAS has been restarted many times before without error. Only thing of note is we had a power failure recently (hence the UPS) and the NAS shutdown unexpectedly but when it came back all was well and ZM just started working as usual

Noddy instructions really appreciated if you can help as linux is not my strong suit. I love zoneminder and I fear it's 100 percent reliability to date has lulled me into a false sense of security and I'm feeling somewhat exposed and in over my head so please help if you can.

Thanks

[Hendergd]

Not sure if this helps or not but If I start zm with everything disabled and then enable one monitor (modect) I get the following in the logs
I also notice the container zm is in says its only drawing a few hundred megs of ram whereas before when working it will pulling 2-3 gigs.Nothing has changed in config and it has no memory limitations set. The NAS as 6 gig of ram on board with nothing else running so there is plenty available


Date/Time
Component Server PID Level Message File Line
2020-08-15 10:00:25 zma_m1 1095 ERR Shared data not initialised by capture daemon for monitor Drive zm_monitor.cpp 499
2020-08-15 10:00:25 zmdc 884 ERR 'zma -m 1' exited abnormally, exit status 255 zmdc.pl
2020-08-15 10:00:19 zmdc 884 ERR 'zma -m 1' exited abnormally, exit status 255 zmdc.pl
2020-08-15 10:00:19 zma_m1 1093 ERR Shared data not initialised by capture daemon for monitor Drive zm_monitor.cpp 499
2020-08-15 10:00:17 zma_m1 1092 ERR Shared data not initialised by capture daemon for monitor Drive zm_monitor.cpp 499
2020-08-15 10:00:17 zmdc 884 ERR 'zma -m 1' exited abnormally, exit status 255 zmdc.pl
2020-08-15 10:00:16 zma_m1 1083 ERR Shared data not initialised by capture daemon for monitor Drive zm_monitor.cpp 499
2020-08-15 10:00:16 zmdc 884 ERR 'zma -m 1' exited abnormally, exit status 255 zmdc.pl
2020-08-15 10:00:15 zma_m1 1077 ERR Shared data not initialised by capture daemon for monitor Drive zm_monitor.cpp 499
2020-08-15 10:00:15 zmdc 884 ERR 'zma -m 1' exited abnormally, exit status 255 zmdc.pl
2020-08-15 10:00:14 zmdc 884 WAR Can't find process with command of 'zmc -m 1' zmdc.pl
2020-08-15 10:00:13 zmdc 884 WAR Can't find process with command of 'zma -m 1' zmdc.pl

[gruiarew]

Check you buffer settings / monitor. That is using /dev/shm. Either lower the buffers, either increase /dev/shm. I had to increase it in order to receive the proper results. WIki says not to go over 70% on /dev/shm.