How to move SSAS tabular instance databases? We have a SQL Server 2012 SSAS tabular instance in our environment that is sitting in domain1. We need to move these SSAS databases in a different SQL server 2012 that is on domain2 which has no trust established with domain1. This is the first time I am tasked to move SSAS in to another server. What would be a good approach in moving these SSAS tabular databases? Is a normal backup and restore would do the process? Or does it have to be attach detach process? Also, when I migrated our SQL Server databases, I have to adjust each account logins since there is not trusts between domains. Do I have to do the same thing with SSAS in this case?
You can back up and restore SSAS Tabular 2012 databases, but you will have to adjust the security role memberships to include users in the correct domain. You can perform the backup and restore manually or through a script in Management Studio (or executed via PowerShell).  

You can also re-deploy an SSAS database from the SSDT project or using the SSAS Deployment wizard. The wizard will allow you to deploy roles and ignore members. Next populate the role memberships with appropriate users. From there, you can process the model to populate it and bring the model online.  

Another option is to script the SSAS database from Management Studio. Once you do this you can remove the  collection from each role and execute the XMLA on your target server.