Of course the best method of backup is a full system backup using BackupExec or a similiar backup/restore tool that can handle Exchange information (most of them can). We always reccomend this first.
After that, the easiest is to use the SubscriberInformationDump utility off my web page to dump out subscriber information to a CSV file that you can use to import back into Unity with the Import tool in the Unity program group. This is easy, safe and fast. The SubscriberInformation dump tool kicks out some data that the import tool can't suck back in, however, so be sure to read the help on the import tool to know what you can get in that way. Basics like display name, alias, extension and the like are certainly there.
This method, however, does not get voice names, greetings, notification device configuration etc... if that's important to you, you can use the Import/Export tool off my web page (and yes, versions of these tools are shipping with the Unity 3.0 CD... they've been QA tested). This method gets all infromation on the system including subscribers, call handlers, COS instances, voice names, greetings etc... review the help file or the web page for a run down on specifically what's backed up and restored and what's not (i.e. routine rules are backed up but not actively restored to the new system).
Again, the import/export tool is not designed to be a cheap backup and restore method. Most notably it does NOT get any kind of messages. You also cannot selectively backup and restore just subscribers or specific subscribers... it gets everything and restores everything. The import portion will only run if it's being run on new install (i.e. CLEAN... no objects in the directory other than those made by setup) of 2.4.6 or 3.0. It's designed as a migration tool.
These are the paths to get to each CCX logs through CLI. They may be helpful if you are having issues accessing RTMT or downloading logs through it.
If you want to download them you have to prefix "file get " and you can add one of the options (re...