High Disk IO usage!

Hi, I woke up today on my server high disk IO usage and i used "iotop" and here is the result: 397 be/3 root 0.00 B/s 0.00 B/s 0.00 % 99.99 % [jbd2/vda1-8] Websites are barely working right now. Also FYI:

System Item	Details	Status
Server Load	12.737305 (2 CPUs)
Memory Used	72.01% (2,824,564 of 3,922,296)
Swap Used	0.44% (18,504 of 4,194,300)

Please advice.