Portable Home Directory Syncing

Is there any good documentation on PHD syncing? Where configuration files are saved, what they contain, fstemp files etc.? We have quite a few users syncing and frequently have problems. Some of the more common problems are files not syncing correctly because they are locked, deleted files/folders syncing back down from the server etc. I've spent plenty of time in the MirrorAgent log file monitoring what is going on, but knowing how it determines a file should be synced one way or the other would help. Also, why a file could not be copied or deleted (Usually a locked file is the culprit) Any basic/advanced troubleshooting tips would be helpful. Thx