[CentOS] du vs df size difference

Hi all,

Curious issue.. looking in to how much disk space is being used on a machine (CentOS 5.3). When I compare the output of du vs df, I am seeing a 12GB difference with du saying 8G used and df saying 20G used.

# du -hcx / 8.0G total

# df -h / Filesystem Size Used Avail Use% Mounted on /dev/xvda3 22G 20G 637M 97% /

I recognize that in most cases du and df are not going to report the same but I am concerned about having a 12GB disparity. Does anyone have any thoughts about this or reason as to why there is a big difference? I have read a few articles online about it and none have really shown such a large difference.

Thanks

Ryan Pugatch Systems Administrator, TripAdvisor