Exactly. You might want to disable media protection to simplify administration when adding new tapes (unless you have a robotic library). Since the Append Jobs won't be able to run until the Overwrite job is finished, they'll queue up and execute as soon as the tape drive becomes available.
When I say "brick by brick" job, I mean the one that you can use to restore individual email messages. When I say "info store" job, I mean the one that takes everything back to a known point in time.
If you find you're having performance problems in the Exchange Info store brick by brick job, you could try 1) disabling other disk I/O activities during the backup period like a) scheduled file based AV scans, b) scheduled AV for exchange scans, c) diskeeper (defrag) operations, d) other backup jobs, e) exchange av real time scans (but only do this temporarily and disable SMTP during this period) etc. Other things to try are 2) moving the exchange stores to a separate partition (that's on a separate array from the main OS) to increase performance, 3) defragmenting the exchange store.
Exchange Brick by Brick jobs are notoriously slow. If you do all the above things, then you may consider changing the types of backups you do. You could continue running your nightly backups of the info store, but do a *full* backup of the exchange store in "brick by brick" mode over the weekend. Then, do a *differential* backup nightly. This will take less time.
It's worth noting that if you have BUE 11d and CPS, you can perform a special kind of backup job that backs up the infostore as if it was a giant file. Then when you want to restore, you get granular control of the restore function. It's really cool in that you spend less time on your backups, but when you go to restore it takes a long time to run because of the way it works. Restore operations are the exception though, so it's a pretty good tradeoff. If you're looking to upgrade anyway, this is something to consider.
