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Exchange 2003 circular logging clarification question

piotrmikula108 used Ask the Experts™
We run backup that takes a snapshot of the entire server so the exchange logs keep growing, I need to switch to circular logging so that stops, now when I do the switch do all the transaction logs get written to the store database or can I just archive them? I wonder if any of the information that is still in the logs (well I have 100GB of logs now :-) would get lost if I move them to another location for archiving?

Thank you
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Microsoft don't recommend enabling circular logging for a production environment, since it takes away the ability to rebuild the database from transaction logs, but since you are backing up the database, you should be able to safely remove the redundant transaction logs once they are committed to the database after a successful backup.

To find out how many logs are redundant, try this command:
To do this from a command line, go to the \Program Files\Exchsvr\bin directory on the server and run the following command:

From the exchange bin folder:
eseutil /mk "C:\Program Files\Exchsrvr\MDBDATA\E00.chk"

The returning information should contain something like:

Checkpoint: (0xD80,85F,AC)

The first number in the "Checkpoint" entry -- 0xD80 -- is the number that refers to the last checkpoint log. Therefore, any logs numbered E000D7F.log or earlier could be removed.
Top Expert 2010

a) what backup software do you use to take backup ?
b) What type of backup is it - full / incremental ?

Exchange-aware backup software flushes exchange logs after taking backup ?

Circular logging is really not a good idea, if you are trying to flush the logs.
Hi Piotrmikula108,

Activating circular logging doesn't remove the excess log files automatically, and you shouldn't delete them manually as this may corrupt your database.

Once you've activated circular logging, perform use NTBackup to perform a Normal backup of the storage group to a temporary location.  During the backup, the inactive logs will be deleted. You only need to do this once as circular logging will prevent the logs building up in future.



A useful guide to backing up Exchange 2003 with NTbackup:



we use Zeniths BDR Guardian backup server that uses Storage Craft Shadow Protect agent to take incrementall snapshots every 15 min
There is a previous discussion that hopefully helps:


thanks you,

so with circular logging the information in the oldest transaction log (that needs to be deleted to create a new log) gets written into the DB before it's deleted?
Also, you might want to ensure your only backing up the exchange stores, and nothing else, I had issues with it not removing the logs when including a system state or C drive backup in the same pass..
Shreedhar EtteTechnical Manager
Top Expert 2010

if you move the logs to another location you would not lose the data in them till the time
log signaturesfor database do not change. this means once you do offline defrag, or eseutil /p this logs files can no longer be used
Top Expert 2010

Hey dude.
It's far easier to have a robust backup Solution than trying to figure this out.
Circular logging feature is there for emergency recovery services of a crashed exchange store.

You can get Veritas license's for cheap here

Veritas allows you brick-level restore --> so you can restore a particular mailbox from exchange store. (in ntbackup you have to restore everything to restore one mailbox)

Set it up.
Set up Exchange Agent