SQL Server Database Migration Checklist:

Migrating a database is very critical and time bound process, if anything goes wrong then it’s very difficult to rollback things and move back to existing environment again. So it’s very important to prepare a checklist before migrating a database and also keep a rollback plan ready in case of migration failure.

At some point of time we have to migrate old version of database server to new version of database server because of technology and feature enhancements, business requirements changes or hardware up-gradation etc. We have two options for database migration, either we can go for in-place upgrade where new version of SQL Server is installed on the same machine where older version of SQL Server exists, this is automated process similar to SQL Server installation and second method is side by side migration where new version of SQL Server is installed on new system and when new system is ready, applications and other links and connectivity’s are pointed to it. It is a manual process where you have to copy or move each and every object from old server to new server manually.

Here I am going to list key points to keep in mind when doing side by side database migration.

Pre-Migration Checklist:

1.    Run upgrade advisor on existing database to check the compatibility and deprecated features with respect to database and applications and make the required changes accordingly.

2.    Note down data file and log file locations and size and make sure new server has enough disk space available.

3.    Note down database recovery model, collation type and database facets.

4.    Note down compatibility level, database owner, linked server, full text catalogs and trustworthy settings details.

5.    Always keep more than one copy of latest database backup if it is feasible and you have enough storage available.

6.    Note down information regarding database logins, users and orphan users and permissions.

7.    Take a copy of all SSIS packages and config files and note down disk locations for files to move.

8.    Generate scripts for all SQL Server agent jobs.

9.    Note down all existing database maintenance plan and its properties.

10.  Generate all the SQL Server logins and keep it safe to deploy on new server.

11.  Note down windows logins and groups and permissions if any.

12.  Check if any Disaster recovery or high availability settings are available and make a note of that.

Once you are ready with pre-migration checklist, start performing migration.

Migration Checklist:

1.    Make sure you stop all applications services connected with database.

2.    Set database to read only mode if required.

3.    Take the latest backup of databases.

4.    Restore latest copy of database on new server.

5.    Check and change the database compatibility level after restore.

6.    Migrate all the user logins and windows logins to new server.

7.    Check the database properties and alter it accordingly if required.

8.    Enable trustworthy database setting if required or keep it as default.

9.    Verify the orphan users and fix the same.

10.  Execute DBCC UPDATEUSAGE command to correct pages and row counts on migrated database.

11.  Execute DBCC CHECKDB on new migrated database to check the integrity of the objects.

12.  It is very important to rebuild all indexes on newly migrated database else you will face performance degradation while running the applications.

13.  Make required changes at application pointer to database and other connectivity settings.

14.  Update statistics on migrated database tables.

15.  Recompile all stored procedures, functions and triggers with sp_recompile.

16.  Refresh all the views available in the migrated database with sp_refershview.

17.  Deploy your high availability or disaster recovery plans if any on new database.

18.   Now test the application and correct the errors if any else celebrate success.

Queries used in Migration Checklist.

– Take database backups.

– Restore database backups.

– Verify compatibility level and change the same if required.

--Verify Compatibility Level

SELECT name, compatibility_level, collation_name FROM sys.databases

GO

--Change Compatibility Level

USE [master]

GO

ALTER DATABASE [DB_Name] SET COMPATIBILITY_LEVEL = 110

GO

– Note down Linked Servers details.

--Verify Linked Servers

SELECT * FROM sys.sysservers

GO

– Note down recovery model details.

--Check Recovery Model

SELECT name, recovery_model_desc FROM sys.databases

WHERE name = 'DBName'

GO

– Note down collation setting.

--Verify Collation setting

SELECT name, collation_name FROM sys.databases

WHERE name = 'DBName';

GO

– Migrate all user logins and password.

– Verify database properties and alter the same if required.

--Check Database Properties

SELECT *FROM sys.databases SD

JOIN sys.syslogins SL ON SD.owner_sid = SL.sid

GO

– Enable trustworthy database settings if required.

--Verify Trustworthy Settings

SELECT is_trustworthy_on FROM sys.databases WHERE name = 'DBName'

GO

--Enable Trustworthy Database Settings if required

ALTER DATABASE DBName SET TRUSTWORTHY ON

GO

– Verify and fix orphan users.

– Correct all the pages and row counts with DBCC UPDATEUSAGE command.

--Correct Pages and Row Counts

DBCC UPDATEUSAGE('DBName') WITH COUNT_ROWS

GO

– Check integrity of objects with DBCC CHECKDB command.

--Check Integrity of Objects

DBCC CHECKDB('DBName') WITH ALL_ERRORMSGS

GO

– Rebuild all indexes by creating maintenance plan or by manual query.

--Script for Index Rebuild

USE DBName

GO

ALTER INDEX ALL ON dbo.TableName REBUILD

GO

– Update database table’s statistics.

--Update Database Statistics

USE DBName

EXEC sp_updatestats

GO

– Recompile all stored procedures, functions and triggers.

--Recompile Objects

USE DBName

EXEC sp_recompile 'ObjectName'

GO

– Refresh all the views of database.

--Refresh Views

USE DBName

EXEC sp_refreshview 'ViewName'

GO