Exchange 2007 SP1 on Windows 2003 64 box, 65 User Mailboxes. After installing SP1, I get Event ID 9871 in Application log stating "There is an online maintenance overlap for database "First Storage Group\Mailbox Database" Please revise the online maintenance schedule". I have changed settings several times, however the warning log still returns every night. Does anyone have any suggestions what I can try to resolve the issue? I am concerned about database corruption since it does not look as if the defragmentation is taking place. Thanks for any suggestions.

Are you seeing the events that show DB whitespace? that would tell you if the online defrag is happening or not. Also, have you restarted the information store since making the changes?

Intersting enough, it does show free space in event 1221 following this warning message. During the window I have selected for database maintenance, it perofrms several passes on the database. Is this normal for it to defrag several times during maintenance period. Also it is important to note that I get event id 9871 at 2:59 AM. This is the exact time that database maintenance window is done. The store service has been restarted several times since changes have been made.

Wow, I did not realize that Microsoft was generating this warning now. It is, however, a warning and can probably be safely ignored. As long as you are getting a 1221 message for each database then online defrags are probably being completed. You just want to make sure that you get a completed online maintenance for each database at least every few days (I think Microsoft was saying this should complete at least once every 2 weeks.) The big thing you want to avoid is the online backups overlapping the online maintenance. Online backups cause online maintenance to halt. This is, of course, MY opinion and does not necessarily reflect any type of Microsoft's guidance.

Dear customer: To proper assist you troubleshoot the issue, please help collect the following information: 1. What's schedule for Backup? And if the backup time is over lapping the online maintenance time then please change the schedule of Backup Exec to take it either before the Online Maintenance period or after. 2. Please also collect an ExBPA report of the Exchange server 2007 by using Exchange Best Practice Analyzer tool in Exchange Management Console > Toolbox, to run a health check. Export the report to an .XML file, compress into a .zip file and send to v-rocwan@microsoft.com. Note: I need the XML format file as this is the only format I can use to get a full view of the report directly. 3. On Exchange server, save the application log as .evt file and send it tome for analyzes. Thanks for your time and cooperation. Rock Wang - MSFT

I checked the backup schedule to find that it takes place inside of maintenance window. I changed selection order to move backup out of maint. window. Will report back with status tomorrow.

You need to specify different hours for tha online maintenance. I had this warings too. What i did: I made de schedule so that each mailbox database have 15 minutes to run daily, and never in the same time from another. Jus like that: mailbox store 1 - run from 00:00 hs to 00:15 hs mailbox store 2 - run from 00:15 hs to 0030:00 hs. This worked fine here. If the time is not enouth for finish de online maintenance, it stops and restarts from where it stopped in the last time.

Dear customer: How are things going? If you are running Exchange 2007 on SP1 while receiving this warning event, I suggest you ignore this warning. The event has nothing to do with scheduling online maintenance (OLM) with other databases. The 9871 is thrown when the schedule window for OLM has ended for a database but a transaction is still being processed. This transaction must complete, we just wont stop it because the schedule window has ended, and that is when the 9871 is thrown. This has always happened, for some reason we added an event with Exchange 2007 SP1 to log it. There isnt too much that can be done, you may try to lengthen the schedule window, give it two hours. But it just depends what we are doing when the schedule window ends, so we could still hit the 9871 event. For example, if you are running a backup at that time, this warning will surely be triggered because of the overlap of online maintenance and the backup job. If you do have a backup job overlap with the online maintenance, I suggest you re-schedule the time and do not allow any overlap. Please let me know if you have any further concern on this topic. Im looking forward to hearing from you. Rock Wang - MSFT

This certainly makes since; I see that when the maintainence window is about to close and defrag is still running the event is logged. If it has completed, the event is not logged in application logs. The part that confuses me is that the defrag may run and complete several times during maint. window. Is this a normal procedure? Again, thanks to everyone who has posted, all have been helpful.

Thanks for highlighting this and describing it in detail. I have apparently the same issue: two mailbox databases on the same server (and also a public fodler db), staggered but overlapping maintenance windows, defrag inexplicably running several times per night, and a 9871 event generated for each of the two mailbox databasesat the times the maintenance windows close. Iget simultaneous events 1221, 9871 and 704 at the moment the maintenance window closes. There is no backup happeninganywhere near that timeso that explanationseems to bea red herring. The key point that hasn't yet been answered appears to be:Why is the online defrag happening several times per night? Also, what is the single event ID that indicates that all the maintenance procedures have completed? (by the way, when are MS going to release the VSS Exchange plugin for Windows Server Backup on Windows Server 2008 that was promised for this summer - it's autumn now and all has gone quiet!) With thanks to all concerned

Hi Wang,This is Anjani- I am facing same issue which others described, but as you replied "could be conflict with Backup process" ---- in my secnario we have separately configured Exchange DB Maintenance and Backup Schedule, eventhough i am getting same issue "DB Overlap" event and DB interrupting or terminated. Right now we are reachedend of the disk space--- meansStorage Group occupiedtotal disk space out of full disk space. we need to do the DB maintenace immediately--- but we are getting above event after completion of DB schedule. Could you give us a solutionnot to distrub with online process OR IS there any solution do in OFFLINE, and if I proceed Offline maintenance normally how muchtime it will take to complete the task.Regards,Anjani.