Moving Report Server Databases to Another Drive
There will be minimal downtime, so plan this in a maintenance window:

Don't use detach/attach!


Have verified backups!
Use Alter database...modify file... (do below for mdf and ldf files)

use master;
alter database dbname 
modify file (
    name = 'logicalName', 
    filename = 'E:\RS\db_name.mdf'); --&gt; This is the new file location 

Now offline the database:

alter database db_name set offline with rollback immediate;

Physically copy the mdf and ldf files to the new location.
Bring the database online:

alter database db_name set online;



If you script out and test out on a dummy database, you will see how much time it takes and will build your confidence.