I think the graphs would be better presented differently. Instead of a line graph, try different opacities. So you have one line per server, going left-to-righ

I think the graphs would be better presented differently. Instead of a line graph, try different opacities. So you have one line per server, going left-to-right, shading from white (for no errors) to whatever color (for the maximum number of errors overall). And perhaps a dot per server and a single line indicating overall status.