The transaction log size in Exchange 2007 is now 1MB instead of 5MB, which was the transaction log size for Exchange 2003. The reason for the size reduction is related to the new log shipping clustering technologies in Exchange 2007. The smaller the log file means a smaller amount of data loss because you can’t ship a transaction log until it’s closed and it needs 5MB of data written before you can close. With Exchange 2007, you only need 1MB of data written. In addition to the reduction of size of the transaction logs the naming scheme has been changed from E<2 digit storage group identifer><5 hexidecimal digits> to E<2 digit storage group identifer><8 hexidecimal digits> which means even though there will be five times the number of transaction logs the number of transaction logs you can have in total is over two thousand times the number of transaction logs you could previously have under Exchange 2003 (you don’t go all the way up to ffffffff, rather 7fffffec).