We are upgrading to confluence clustered version 5.7, soon. Currently, we are on 3.4.9 and have around 400+ wiki spaces that we are going to migrate. I need to decide about how much disk storage will be required by the upgraded version of confluence i.e. 5.7 on the application servers. I know, I should probably take help from the infrastructure team on this but, can anyone here please help me figure it out on my own? And, if we plan to switch to data center version then, how is it going to affect the disk storage requirement?