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In today’s tech-driven world, it’s crucial for a business to maintain and protect their data. The SQL Server provides solutions for two major challenges in this regard: High Availability (HA) and Disaster Recovery (DR).
This blog post will explore the fundamentals of these SQL features and demonstrate how to use them with coding examples.
High Availability (HA)
High availability refers to the continuity of services and functions even when part of the system fails. For the SQL Server, this can be achieved through features like Failover Cluster Instances (FCIs) and Always On Availability Groups.
Implementing FCIs in SQL Server for High Availability
Failover Cluster Instances increases the availability of SQL Server instances by allowing a secondary server to automatically take over if the primary server fails. The following code creates a Failover Cluster Instance:
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CREATE AVAILABILITY GROUP ag1 WITH (AUTOMATED_BACKUP_PREFERENCE = SECONDARY) FOR REPLICA ON ‘SQLServer1’ WITH ( ENDPOINT_URL = ‘TCP://SQLServer1:5022’, AVAILABILITY_MODE = SYNCHRONOUS_COMMIT, FAILOVER_MODE = AUTOMATIC, BACKUP_PRIORITY = 50, SECONDARY_ROLE(ALLOW_CONNECTIONS = ALL)), ‘SQLServer2’ WITH ( ENDPOINT_URL = ‘TCP://SQLServer2:5022’, AVAILABILITY_MODE = SYNCHRONOUS_COMMIT, FAILOVER_MODE = AUTOMATIC, BACKUP_PRIORITY = 50, SECONDARY_ROLE(ALLOW_CONNECTIONS = ALL)); |
Disaster Recovery (DR)
Disaster Recovery involves restoring data and services following a serious incident, like a natural disaster or cyberattack. The SQL Server Log Shipping feature is one option for data recovery.
Implementing Log Shipping in SQL Server for Disaster Recovery
Log shipping is the process of automating the backup of databases and transaction log files on a primary database server and then restoring them onto a standby server. Here’s a basic command to backup logs:
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BACKUP LOG [DBName] TO DISK = N'F:\DBBackups\AdventureWorks_LogBackup_yyyymmddhhmmss.trn' WITH NOFORMAT, NOINIT, SKIP, NOREWIND, NOUNLOAD, STATS = 10 |
This is just the start of High Availability and Disaster Recovery in SQL Server. Other features like Database Mirroring, Replication, and Always on Availability Groups also play a crucial role. However, the understanding and implementation of FCIs and Log Shipping is an excellent starting point. Get started today and safeguard your data like never before.