moving content db for a site collection to another db server

 

Here are the steps you will need to take Lets call content DB “MyTESTContentDB”

1. Do a database backup for the content db “MyTESTContentDB” from sql management studio
2. Go to target DB Server and create a empty database naming “MyTESTContentDB” after the content DB
3. Restore the backup from step 1 to empty database create in step 2 “MyTESTContentDB”
4. Go to SharePoint server and run following script Dismount-spcontentdatabase “MyTESTContentDB” and type “Y” to confirm
5. Run the following script

   stsadm -o addcontentdb -url http://local.company.com/mytestsite -databasename MyTESTContentDB -databaseserver TARGETDBSERVER

You will have to input actual URL, actual db name and correct target db server name

Please refer this:http://sharepoint.stackexchange.com/questions/81172/moving-content-db-for-a-site-collection-to-another-db-server