User Migration Troubleshooting
Improperly configuring the maximum file upload size for your user migration can result in two problems:
- The server rejects large messages, even though the default file upload size has been changed
- The server drops its connection with the Migration Wizard during migration
Read more about each of these problems below.
Large Messages Rejected by Server
If the server is rejecting large messages, even though you changed the default file upload size, you may not have configured the maximum file upload size in both the Migration Wizard and the Zimbra server. Both the Migration Wizard and the Zimbra server must be configured with the same maximum file upload size in order to keep larger messages from being rejected.
To learn more about how to configure the Migration Wizard and the Zimbra server with the same maximum file upload size, see User Migration & Maximum File Upload Size.
Server Connection Dropped During Migration
If you are experiencing an interruption during user migration because of a dropped server connection, you may have configured a new maximum file upload size that is too large for Tomcat to handle.
When Tomcat receives a message that is larger than the available contiguous memory, the server experiences an OutOfMemoryError and Tomcat crashes. Tomcat will be automatically restarted by a zmtomcatmgr process, but it may take Tomcat several minutes to process everything it was handling when it crashed. If this happens in the middle of a user migration, the Migration Wizard will not be able to connect to the server and your migration will be interrupted.
The solution is to reconfigure your maximum file upload size to a smaller size. If you are uncertain what size file your server can handle for upload, try using the default message size of 10 MB. For more information on reconfiguring the maximum size of a file upload, see User Migration & Maximum File Upload Size.