SQL Server 2008: High Availability--Always On

Overview

Microsoft SQL Server 2008 Always On Technologies provides a full range of options to minimize downtime and maintain appropriate levels of application availability.

Top New Features

Recover corrupt data pages from a mirror server with enhanced database mirroring features
Take advantage of failover clustering enhancements in Microsoft SQL Server 2008 and Microsoft Windows Server 2008
Add new nodes to a peer-to-peer replication solution without taking applications offline
Improve restore times and reduce backup volume size with new support for backup compression
Improve concurrency with locking enhancements
Reduce downtime for hardware maintenance with Hot-Add CPU capabilities
Use Resource Governor to proactively control workload prioritization

Partners

Find Always On Storage Partners

Database Mirroring Wizard

Increased Availability

Minimize downtime, speed up recovery, and achieve the appropriate level of availability defined by service level agreements.

Database Mirroring

Increase availability by providing complete or nearly complete database redundancy in the event of a disaster or planned upgrade
Provide a high-availability solution that does not require proprietary hardware, is easy to set up and manage, and provides automatic client redirection
Protect against page corruption by using SQL Server 2008 Enterprise to automatically fetch the mirror version of a corrupt page from a partner server

Log Shipping

Use log shipping to provide database-level redundancy with two or more instances of SQL Server by automatically backing up, copying, and restoring transaction logs on standby servers
Increase availability by providing multiple failover sites
Apply a time delay for applying transaction logs on the standby server to provide protection against user errors
Reduce the load on the primary server by using a secondary server for read-only query processing

Failover Clustering

Provide server-level redundancy on a certified Microsoft Cluster Services configuration
Enable seamless failover capabilities in the event of a CPU, memory, or other non-storage hardware failure by sharing disk access between nodes and restarting SQL Server on a working node in the event of a failure

Geographically Dispersed Failover Clustering

Provide server-level redundancy and remove the single point of failure in a typical failover cluster by using a certified Microsoft Geographically Dispersed Cluster Services configuration with SAN replication and a VLAN

Peer-to-Peer Replication

Replicate changes at close to real time while all databases also handle their primary responsibilities
Increase scalability, availability, and processing capacity by configuring applications to use different peers and to fail over to another peer in the event of a peer failure
Protect against accidental conflicts with SQL Server 2008 conflict detection
Increase availability by dynamically adding a new node to an existing topology
Easily visualize and manage your topology with the Topology Viewer in SQL Server 2008

Enhanced Backup and Restore

Use mirrored backup sets to perform a concurrent backup of a database to multiple backup devices and to increase protection in the event of backup media failure
Create checksums on backup media to verify subsequent restore operations

Checksum on Data Pages

Detect damaged database pages quickly, regardless of how the damage occurred, by using checksum on data pages
Detect pages that were written incompletely, or from outside of SQL Server, and use online page-level restore to replace the faulty page

Deep Dive

Decreased Downtime

Recover quickly from unplanned downtime and minimize downtime from system maintenance and operational procedures that are necessary for the smooth operation of mission-critical applications.

Online Index Operations

Increase performance and availability of mission-critical applications by creating, dropping, and rebuilding indexes while they are still online and available to applications

Backup and Restore

Use backup compression to improve restore times and reduce the size of backup volumes
Restore read-only database file groups without applying transaction logs
Use piecemeal restores to restore a database in stages and make critical data available sooner
Reduce downtime caused by file corruption by restoring individual data pages
Use online restore to keep a database online and available during database file, page, or piecemeal restore operations

Fast Database Recovery

Fast recovery makes databases accessible sooner after a system failure or during the failover recovery process
Fast Recovery ensures partial availability during restore and database page checksum operations

Partial Database Availability

Provide access to undamaged database files if secondary non-primary data files are unavailable due to isolated hardware or disk failures

Locking

Prevent writers from blocking readers and readers from blocking writers by using snapshot isolation
Increase concurrency on partitioned tables with the enhanced locking escalation of SQL Server 2008

Dynamic Configuration

Add memory and processing power to supported systems without having to restart SQL Server by using Hot-Add Memory and Hot-Add CPU

Deep Dive

Resource Governor

Improved Manageability

Investigate, monitor, and recover damaged data across your enterprise by using powerful and productive management tools that simplify recovery.

Resource Governor

Control resource utilization to prioritize key workloads with Resource Governor
Ensure that mission-critical database workloads are not adversely affected by other database activity

Database Snapshots

Provide point-in-time snapshots of databases and investigate and repair user errors by comparing the current values against snapshot data
Use the snapshot as a source for reports to provide point-in-time reporting capabilities
Reduce the data storage requirements of a full copy of the database because database snapshots contain only data that has changed, not the entire database
Provide read-only access to database mirrors

Table and Index Partitioning

Limit the impact of I/O-intensive activities such as data load, backup and restore, index rebuild, and index defragmentation, by breaking large tables and indexes into smaller partitions

Dedicated Administrator Connection

Connect to a server that appears to be unavailable by using the high priority Dedicated Administrator Connection (DAC)

Deep Dive

SQL Server Always On Storage Solution Partners

SQL Server Always On partners provide storage solutions that have been carefully reviewed to meet the SQL Server storage solution requirements. These partner solutions provide the highest level of availability and reliability for SQL Server applications.