Force mirroring re-sync in a production database

•

Environment: cloud

• 2 minutes to read

You have set up database mirroring and data was synchronizing as expected, but now it seems to have stopped. What do you do?

There is no GUI to check data in a mirror, so you must use SQL Server Management Studio to inspect the tables. Generally, it should be possible to do select * from <sometable> in both the customer table and the mirror and get the same result.

If you notice that some tables are not updating as expected, it might be time to force a resynchronization.

This procedure is intended for a live system.

Pre-requisites

your application is registered and has been deployed to the production environment
you have a publicly available working service
your application has been approved by the customer's tenant administrator

Restart synchronization

Using SQL Server Management Studio, go to the <context identifier>_mirroring database table
For each table that you have identified as having a problem, set LSN to -1 within the mirroring table.
Then truncate the data in the table(s) you set LSN to -1:
```
truncate table <tablename>
```
Shortly thereafter, the Mirroring Task will send an authentication request, which your client must respond to. After successful authentication, SuperOffice will begin to deliver periodic updates to your mirroring service.

Hard reset the mirror

Using SQL Server Management Studio, go to the <context identifier>_mirroring database table.
For each table you have identified as having problems, let us use contact in this example:
```
delete from <context_identifier>_mirroring where tablename = 'contact'
```
Then drop table contact
Shortly thereafter (the next mirroring cycle), the Mirroring Task will send an authentication request, which your client must respond to. After successful authentication, SuperOffice will recreate the database table(s) and begin to deliver periodic updates to your mirroring service.