PST migration questions

Yes, it scans:

- Your file system

- Your registry

So it can find stuff that isn't being used by Outlook.

Yes it can handle network drives - though if you look in the Symantec technotes there are some caveats around things like DFS and so on.

Using Locate & Migrate, you can associate a PST with an owner.

There is a policy setting "Mark PST's" found in the Outlook section of the Advanced tab of the Exchange mailbox policy. When set to On (which I believe is the default since about EV6 or so) then any user who gets that policy and connects a PST to Outlook will have a "mark" inserted into the PST to show ownership. This will stay in place even after the PST is disconnected from Outlook. When you discover a PST on a file share/file server target, EV will open it and look for a mark. If found and a match can be made, then EV knows whose PST it is and everything is automatically aligned.

If there is no mark found then EV will check the NTFS permissions on the discovered PST. It will only make an association to a user and a mailbox if it is clear who "owns" the PST. If it is ambiguous, then EV will wait to allow the Admin to decide whose PST it is. Anything not matched to an owner by a mark or by the permissions will wait for admin intervention, and if memory serves me there may be some wrinkle where the NTFS permissions check isn't supported if the file server is certain media or manufacturer.

If you are planning a PST migration of that size, I would strongly suggest you upgrade to at least EV10 SP4 CHF3. SP4 introduces some new functionality and features around PST Migration, including "PST Donation" where in a client-driven migration the user can control which of their dozens of PST's to migrate and also point the client to unattached PST's (you can choose to turn those on or off depending on the users). The admin can also import a csv file with PST details (say you run a report using whatever you usually use to report on file servers, and this report shows pst files in user home directories; with a little scripting/excel juju you can make a CSV that basically aligns all psts in a user home directory with that user archive and mailbox, add some optional details if you want, then off to the races).  You may also consider waiting for EV11 SP1 to release as there may be some additional PST-related features in there for you.  

Regardless of what version you end up on, you should start thinking about an upgrade, as EV9 is at the stage in its lifecycle where there will be no further compatibility certification (i.e. no newer versions of Exchange will work with EV9, if they are not already classed as compatible they are not going to be) and there will also be no further hotfixes, new features, etc.

As for documentation, I would start with the 10.0.4 feature breifings so you can decide if you want to upgrade and get the new functionalities or stick with EV9:  http://www.symantec.com/business/support/index?page=content&id=DOC6622