In debugging some indexing related issues with Symantec Enterprise Vault I found this link http://www.symantec.com/docs/TECH160420 which provides some useful information about debugging indexing.
I have found the EV Dtrace facility to be very useful for debugging in the past and for indexing, one of the tasks which generate output is EVIndexVolumesProcessor so you should set it to generate verbose output while using Dtrace.
The dtrace was instrumental in leading me to this post: http://www.symantec.com/connect/forums/problems-indexing-after-upgrading#comment-5964601 The indexer was having trouble communicating with the StorageCrawler even though they were on the same machine. Disabling the firewall resolved the issue so there must be a port that needs to be opened. More details as they become available.