Running multiple cameras on raspberry

[brendhow-done3d]

I need to run multiple cameras simultaneously on raspberry

Message error:

Insufficient buffer memory.
Unable to use mmap. Using read instead.
Unable to use read.

[prashants1]

which two cameras are you using?

[brendhow-done3d]

Im using the camera ELP, i can use up to 6 cameras using a ** USB HUB **, but I have to put an interval of 0.1 seconds between each capture, using it as follows:

fswebcam -r 3264x2448 -S 3 --no-banner --jpeg 95 -d /dev/video0 cam_01.jpeg & sleep 0.1;fswebcam -r 3264x2448 -S 3 --no-banner --jpeg 95 -d /dev/video2 cam_02.jpeg

But even using it that way, but some photos are totally dark, as if they were corrupted.