How to configure fail over when first ISP is full speed

[SeakleangHeng]

I have two ISPs primary and secondary. ISP1=5Mb/s and ISP2=2Mb/s

I want to configure automatic fail over when ISP1 use full speed then ISP1 will share some traffic to ISP2.

Can anyone tell me how to configure it?

[adash_FTNT]

you can configure spill over as per the link below

http://nullhaus.com/2014/02/fortigate-wan-load-balancing/