North Carolina State Districts - NC School District Rankings
I found this website that ranks 113 systems in the state. Here's a list per ranking with corresponding "blue" or "red" based on the 2008 vote and whether it belongs to the Charlotte or Triangle metro.
2. Chapel Hill-Carrboro: 11,083 students - Blue County (Triangle Metro)
6. Mooresville City: 5252 students - Red County (Charlotte Metro)
18. Union County: 35,616 students - Red County (Charlotte Metro)
20. Lincoln County: 12,243 students - Red County (Charlotte Metro)
22. Iredell County: 21,023 students - Red County (Charlotte Metro)
23. Wake County (Raleigh): 128,748 students - Blue County (Triangle Metro)
33. Johnston County: 29,307 students - Red County (Triangle Metro)
37. Orange County: 6907 students - Blue County (Triangle Metro)
56. Chatham County: 7599 students - Blue County (Triangle Metro)
67. Gaston County: 32,800 students - Red County (Charlotte)
70. Charlotte-Mecklenburg: 128,789 students - Blue County (Charlotte Metro)
99. Durham County: 31,260 students - Blue County (Triangle)
The best performing school systems are smaller systems. The two huge systems, Wake and Charlotte-Mecklenburg are ranked 23rd and 70th respectively.
One big difference between the Triangle and Charlotte is that only Mecklenburg is the only blue county in the metro area. In contrast, most of the counties in the Triangle were blue with a few red. That said, most of the state is trending more Democratic over time.
Here's another article that might interest you.
How did North Carolina end up the ultimate toss-up state? Reviewing county data | Observationalism