hot_v* file not found but able to see file using locate

Hi, Referencing to http://docs.splunk.com/Documentation/Splunk/6.2.1/Capacity/Estimateyourstoragerequirements, I'm trying to estimate my storage space on Linux. At /opt/splunk/var/lib/splunk/defaultdb, when I run "du -ch hot_v*", terminal says no such file or directory. I did a locate hot_v and a list below came up and one of them in the db folder is hot_v1_12. I then did a ls -a and I can't find hot_v1_12. Anyone encounter this issue before? ![alt text][1] [1]: /storage/temp/217902-capture.jpg