Complete LOG SHIPPING

 Understanding Log Shipping:  SQL Server Log shipping allows you to automatically send transaction log backups from a primary database on a primary server instance to one or more secondary databases on separate secondary server instances. The transaction log backups are applied to each of the secondary databases individually. An optional third server instance, known as the monitor server, records the history and status of backup and restore operations and, optionally, raises alerts if these operations fail to occur as scheduled.

 

Terms and Definitions:

primary server

The instance of SQL Server that is your production server.

primary database

The database on the primary server that you want to back up to another server. All administration of the log shipping configuration through SQL Server Management Studio is performed from the primary database.

secondary server

The instance of SQL Server where you want to keep a warm standby copy of your primary database.

secondary database

The warm standby copy of the primary database. The secondary database may be in either the RECOVERING state or the STANDBY state, which leaves the database available for limited read-only access.

monitor server

An optional instance of SQL Server that tracks all of the details of log shipping, including:

• When the transaction log on the primary database was last backed up.

• ·    When the secondary servers last copied and restored the backup files.

• ·         Information about any backup failure alerts.

  Jobs in Log shipping :

·        Backup Job

A SQL Server Agent job that performs the backup operation, logs history to the local server and the monitor server, and deletes old backup files and history information. When log shipping is enabled, the job category "Log Shipping Backup" is created on the primary server instance.

·         Copy job

A SQL Server Agent job that copies the backup files from the primary server to a configurable destination on the secondary server and logs history on the secondary server and the monitor server. When log shipping is enabled on a database, the job category "Log Shipping Copy" is created on each secondary server in a log shipping configuration.

·         Restore job

A SQL Server Agent job that restores the copied backup files to the secondary databases. It logs history on the local server and the monitor server, and deletes old files and old history information. When log shipping is enabled on a database, the job category "Log Shipping Restore" is created on the secondary server instance.

·         Alert job

A SQL Server Agent job that raises alerts for primary and secondary databases when a backup or restore operation does not complete successfully within a specified threshold. When log shipping is enabled on a database, job category "Log Shipping Alert" is created on the monitor server instance.

Important: Once the monitor server has been configured, it cannot be changed without removing log shipping first.

Minimum Requirements:

1. SQL Server 2005 or later
2. Standard, Workgroup or Enterprise editions must be installed on all server instances involved in log shipping.
3. The servers involved in log shipping should have the same case sensitivity settings.
4. The database must use the full recovery or bulk-logged recovery model
5. A shared folder for copying T-Log backup files
6. SQL Server Agent Service must be configured properly   

 

A Typical Log Shipping Configuration:

                                                     

The following figure shows a log shipping configuration with the primary server instance, three secondary server instances, and a monitor server instance. The figure illustrates the steps performed by backup, copy, and restore jobs, as follows:

1. The primary server instance runs the backup job to back up the transaction log on the primary database. This server instance then places the log backup into a primary log-backup file, which it sends to the backup folder. In this figure, the backup folder is on a shared directory—the backup share.
2. Each of the three secondary server instances runs its own copy job to copy the primary log-backup file to its own local destination folder.
3. Each secondary server instance runs its own restore job to restore the log backup from the local destination folder onto the local secondary database.

                                                                                            

Steps to Configure Log-Shipping:

1. Make sure your database is in full or bulk-logged recovery model. You can change the database recovery model using the below query. You can check the database recovery model by querying sys.databases 

SELECT name, recovery_model_desc FROM sys.databases WHERE name = 'jugal'

USE [master]
GO
ALTER DATABASE [jugal] SET RECOVERY FULL WITH NO_WAIT
GO

2. On the primary server, right click on the database in SSMS and select Properties. Then select the Transaction Log Shipping Page. Check the "Enable this as primary database in a log shipping configuration" check box.

 

3. The next step is to configure and schedule a transaction log backup. Click on Backup Settings… to do this.  

If you are creating backups on a network share enter the network path or for the local machine you can specify the local folder path. The backup compression feature was introduced in SQL Server 2008 Enterprise edition. While configuring log shipping, we can control the backup compression behavior of log backups by specifying the compression option. When this step is completed it will create the backup job on the Primary Server.
                                                                                                              

 

4. In this step we will configure the secondary instance and database. Click on the Add… button to configure the Secondary Server instance and database. You can add multiple servers want to setup one to many server log-shipping.

When you click the Add… button it will take you to the below screen where you have to configure the Secondary Server and database. Click on the Connect… button to connect to the secondary server. Once you connect to the secondary server you can access the three tabs as shown below.

Initialize Secondary Database tab

In this step you can specify how to create the data on the secondary server. You have three options: create a backup and restore it, use an existing backup and restore or do nothing because you have manually restored the database and have put it into the correct state to receive additional backups.

Copy Files Tab

In this tab you have to specify the path of the Destination Shared Folder where the Log Shipping Copy job will copy the T-Log backup files. This step will create the Copy job on the secondary server.

Restore Transaction Log Tab

Here you have to specify the database restoring state information and restore schedule. This will create the restore job on the secondary server.

5. In this step we will configure Log Shipping Monitoring which will notify us in case of any failure. Please note Log Shipping monitoring configuration is optional.

Click on Settings… button which will take you to the “Log Shipping Monitor Settings” screen. Click on Connect …button to setup a monitor server. Monitoring can be done from the source server, target server or a separate SQL Server instance. We can configure alerts on source / destination server if respective jobs fail. Lastly we can also configure how long job history records are retained in the MSDB database. Please note that you cannot add a monitor instance once log shipping is configured.

6. Click on the OK button to finish the Log Shipping configuration and it will show you the below screen.