Hi all i am working on Exchange 2007 server lab enviroment studing for 70-236 exam, during my prepairation on theory and labs i havea question that maybe you can help me out. when a perfom a full backup on the mailbox database and NO any other changes has been made to the db (mail trafic) and then immediately i dismount the database why some transaction logs remain in there? concern that after a full back all transaction logs imported to db are deleted,right? and when you dismount a db (clear shutdown state) the shutdown proceess import any logs files that were not imported before,right? so why that logs remain there since they are backed up and the procees of the dismount of the db import them in to the db? hope to get some answer and thanks you for your time Regards,

Hello, Basically, when you perform full backup of Exchange 2007 it purges the transaction log files which are committed to database. You can check the last committed transaction log sequence number with Eseutil /mk command by running it on check point file for the storage group (*.chk) References: Eseutil /M File Dump Mode http://technet.microsoft.com/en-us/library/bb124584(EXCHG.80).aspx Understanding Transaction Logging http://technet.microsoft.com/en-us/library/bb331951(EXCHG.80).aspx Now second thing, when you start Full Backup store.exe (Microsoft Exchange Information Store) becomes lazy and will not commit any transaction log to database untilbackup finishes. Let's say your full backup starts at 5pm and completed at 6pm then the transaction log generated between 5-6pm will be committed to database after 6pm and if you dismount the stores then it will just commit the transaction log which is taken in to memory by store.exeso you can see allother transaction logs on the disk. Additionally, during Full Backup if huge amount of transaction logs being generated and uncommitted transaction logs reaches to 5000 then store dismounts automatically with event id 1159 (check below KB). The Exchange store is dismounted, and event ID 1159 is logged in Exchange Server 2007 http://support.microsoft.com/kb/925817

A successful full and a incremental backup deletes log files but if you dismount a database no log file gets deleted although they are committed during a clean shutdown.

thank you for your answers, you really help me clear this in my mind