When using the File input on Windows 7, the .sincedb file continually overwrites one entry instead of keeping an entry for each file.
I've narrowed it down to the File::Stat#ino call in FileWatch::Tail
When using File::Stat#ino on my Windows 7 machine it always returns 0 no matter what file I give it. I've replicated this behavior with Ruby 1.8.7 and JRuby 1.6.6. Because of this, everytime the .sincedb file gets updated it updates the same entry and loses track of all other file positions.
I tried it on my Mac as well (OSX Lion) and I had no issues.
It's pretty bizarre and I can't seem to find any other people having a similar issue anywhere. The best I found was a post from 2005.