See the question mark "?" next to two of these fields? You need to click it and then read the important help text information. The way you've got some of these fields populated is guaranteed to cause problems. Clear all three of these fields out on all your cameras and then try again. When recording video streams from an IP camera, the only way to restrict the frame rate is within the camera itself. I believe you mentioned the streams were at 5 fps. That is a good value.Analysis FPS 5.00
Maximum FPS (?) 15.00
Alarm Maximum FPS (?) 30.00
You've got your cameras set to Mocord, which will record continuously and create motion events. Is that what you want?
Since all 5 of your cameras are ffmpeg HD resolution recording continuously, you can expect significant cpu, memory, and disk i/o resources to be consumed.
Remember that /run/shm is a normal filesystem. You can browse it like any other filesystem and see which files are taking up all your space, who the owner is, and what process has the files open.