Best Method to move 500 Repositories

[Phil Pinkerton]

Looking for suggestion on best way to move 500 Repositories from Unix 
Hardware  to VM  Linux Server

old - Unix Server compiled and Built Subversion 1.6.5 from Source
new - Linux VM Server will have Subversion Edge 1.6.17

ACL contains 2000 + users.

Any experience at this scale  ? Advise ?

looking for clean , simple  minimal risk approach.

thanks