After installing Captive to read my NTFS partition, I noticed great periods of unexplained high CPU activity. I narrowed these down to mount.captive-ntfs and captive-sandbox-server processes. No files on my windows partition (mounted on /C) were being accessed to my knowledge. After scrolling through a process tree I realised that updatedb and find were running and that of all the filesystems and directories to ignore, Captive and the /C path were not in that list.Whilst it doesn’t explain why the CPU goes so high, I can guess that a find / on a 30Gig C Partition would take a lot of time, considering the files available and that each time a new file is opened a new instance of the captive-sandbox-server starts.
To have updatedb ignore the /C mount you can edit the file /etc/sysconfig/locate & add your directory to the variable UPDATEDB_PRUNEPATHS