rsync is just hanging, building file list

rsync 2.x does build a full file list up front.

Add the -P option and you'll see a progress indicator.

If you think it really is hanging, in another terminal find the pid of rsync and then

1. Run strace -p PID and see what it's doing. (Hit ^C to stop.)

2. Run ps -o wchan PID to see where it is in the kernel.

You should upgrade to rsync 3.0.x where you will get the benefit of incremental file lists, explained here. I am rsyncing millions of images (~200GB total) and saw an enormous speedup when going from rsync 2.x to 3.x.

Even so, it will probably take a long time to go through all that data. In my case it still takes over an hour between two pretty powerful DL380 G5 servers.

You noted earlier that du was hanging as well. Something is up with this filesystem, and rsync is hitting whatever du was.

One quick thing you can check is for kernel error messages indicating a disk problem. Type dmesg and see what's at the bottom.