[vitaliyf]

+1 on rclone - one of my favorite tools in the toolbox.

With sufficient --transfers and --checkers values you can easily saturate 10-20 gigabit/second links, so with a handful of machines you can transfer 25TB in about an hour, no engineers required.

Worth noting that rclone also supports many other storage providers or even plain SSH, so it pretty much obsoletes rsync. It also has many other nifty features useful outside of the "sync files" use case.