7. Replication & HA• Objectives

– Understand Replication and HA

• Contents– Standby server

– Failover clustering

– Virtual server

– Cluster

– Replication

• Practicals

• Summary

Standby server

• A standby server can be maintained to take the place of the primary production server

• A standby server is a secondary SQL Server installation that is kept up-to-date with a primary SQL through the application of transaction log backup files

• A standby server must maintain an exact copy of one or more production databases on the primary server

• To promote the standby server to become the new primary server, all unapplied transaction log backup files must be applied to the standby server.

Using Failover Clustering • A server cluster is a group of independent computer systems working

together as a single system and sharing a common storage system

• Each computer frequently has identical

hardware

• Applications run on a server cluster,

rather than on a specific node in the

server cluster

• SQL Server 2000 runs as a virtual server

across two or more nodes in the server cluster.

Replication• Replication is the process of automatically

distributing copies of data and database objects among SQL Server instances, and keeping the distributed information synchronized.

• Snapshot, periodic replication of an entire set of data as of a specific moment in time from a local server to remote servers

• Transactional, each transaction is replicated

• Merge, adding data afterwards to syncronize