Disk Usage Check (DU) leads to high CPU usage

'du -sk /home' and 'sh -c (du -sk \/home) 2>/dev/null' run because a virtualmin scheduled disk usage for /home, but 'du' is causing 100% CPU usage. Plus, before it's even finished, another du gets run and it piles up, bringing the system down to its knees.

I've since disabled the automated checks, but I can't run 'du -sk /home' manually either. 'du' runs fine (fast) on other directories (though /home is the largest - 4912620 - it shouldn't take as long as it does)

I would like to find out why is DU causing high CPU usage on /home

CentOS 6.5

4.04/1.66