We are in the middle of migrating from an in house Exchange 2003 server, to Exchange Online. We are using MigrationWiz to perform the migrations. However, while running a few migrations, our server slowed to a crawl. Takes a long time to click between messages and locks up for minutes at a time. We stopped the migrations, and now in our event viewer we have noticed several events, like the one below. Any suggestions? I have increased the size of the drive that the database is on, and have increased the maintenance window by several hours. Does anyone have any ideas what this may be, or how to return my server to normal performance? And how often should I run the online defrag and maintenance? It was running nightly, I changed it to twice a week. My database if about 350Gb.
Here is the message:
We were doing a few migrations, and my users started reporting that they were getting kicked out of email. I have stopped all migrations, and my exchange server is giving me a message (for each of my stores) in the app logs that reads:
Event Type: Warning
Event Source: MSExchangeIS Mailbox Store
Event Category: Background Cleanup
Event ID: 9791
Time: 11:11:34 AM
Cleanup of the DeliveredTo table for database 'First Storage Group\mail' was pre-empted because the database engine's version store was growing too large. 0 entries were purged.