SQL Server Database Mirroring Concept

SQL Server 2008 for DevelopersUTS Short Course

Specializes in

C# and .NET (Java not anymore)

TestingAutomated tests

Agile, ScrumCertified Scrum Trainer

Technology aficionado • Silverlight• ASP.NET• Windows Forms

Peter Gfader

http://sharepoint.ssw.com.au/Training/UTSSQL/Pages/

Course Timetable Course Materials

Course Website

Course OverviewSession

Date Time Topic

1Tuesday03-08-2010

18:00 - 21:00

SQL Server 2008 Management Studio

2Tuesday10-08-2010

18:00 - 21:00

T-SQL Enhancements

3 Tuesday17-08-2010

18:00 - 21:00 High Availability

4Tuesday24-08-2010

18:00 - 21:00

CLR Integration

5Tuesday31-08-2010

18:00 - 21:00

Full-Text Search

Basic T-SQL syntax

New Data Types

Inline variable assignment

Table Value Parameters

DDL (Data Definition Language) Triggers

CTE (Common Table Expressions)

TOP % WITH TIES

XML Queries

PIVOT/UNPIVOT

What we did last week

Homework?

CREATE DATABASE SSW_TrainingGO

USE SSW_TrainingGO

CREATE LOGIN LOG_USER WITH PASSWORD=N'LOG_u$er_01', DEFAULT_DATABASE=SSW_TrainingGO

CREATE USER LOG_USER FOR LOGIN LOG_USERGO

EXEC sp_addrolemember N'db_datareader', N'LOG_USER'GOEXEC sp_addrolemember N'db_datawriter', N'LOG_USER'GO

CREATE TABLE [ServerLogins](ID bigint IDENTITY(1,1) NOT

NULL, [DateTime] datetime, PostTime nvarchar(100), LoginName nvarchar(100), EventType nvarchar(100), ClientHost nvarchar(100), [EVENTDATA] xml

) ON [PRIMARY]GO

CREATE TRIGGER logon_trigger_login_logON ALL SERVER WITH EXECUTE AS 'LOG_USER'FOR LOGONAS

DECLARE @data xmlSET @data = EventData()INSERT INTO SSW_Training.dbo.ServerLogins([DateTime],

PostTime, LoginName, EventType, ClientHost, [EventData])VALUES(GETDATE(), CONVERT(nvarchar(100), @data.query('data(//PostTime)')), CONVERT(nvarchar(100), @data.query('data(//LoginName)')), CONVERT(nvarchar(100), @data.query('data(//EventType)')), CONVERT(nvarchar(2000), @data.query('data(//ClientHost)')), EVENTDATA())

GO

SELECT geometry::STGeomFromText('LINESTRING (0 0,

0 2, 1 3, 2 2, 2 0, 0 2, 2 2, 0 0, 2 0)', 0)

Envelope;

Homework?

SQL 2008 High Availability Features

Session 3

What is High Availability?

What can go wrong?

What can we do about it?

AgendaAgenda

Different people have different definitions

Perceived uptime Performance

What can go wrong?

How can we improve it?

What is high availability?

Different people have different definitions

Perceived uptime Performance Issues

What can go wrong?

How can we improve it?

What is high availability?

Hardware Disk failure Network failure Power Outages

What can go wrong? (continued)

Software Virus (and Virus Scanners) – File locking issues Disk space Corrupted files Bad upgrades OS Upgrades

SQL poor tuning or design DB Maintenance

What can go wrong?

People (PEBKAC)

Administrators Users

• Bottlenecks & Concurrency

Acts of God

Lightning Cleaners

What else can go wrong?

1. Hardware Solutions• UPS & Hardware Monitors• RAID / Mirroring• Off site server• Firewall• Physical Security

What can we do about it? (continued 3-1)

2. Software Solutions• Database Mirroring• Log shipping

– Auto backup transaction log, and restore• Replication (Can also reduce availability)

– Monitor, Change• Database Snapshots• Alerts

– OS: Disk Space, ...– DB: Logs,...

• Partitioned Tables• Firewalls

What can we do about it? (continued 3-2)

3. OS Level / Backup Solutions• Security• Change Management• Performance Monitoring/Tuning• Hot/Warm/Cold standby servers• Standard daily backups

– Verified procedure– Transaction logs

What can we do about it? (3-3)

Implementing Database Snapshots

Configuring a Database Mirror

Partitioned Tables

SQL Agent Proxies

Performing Online Index Operations

Mirrored Backups

What Will We Cover?

Database Snapshots

Database Snapshots

Mirroring for reporting

Recover from administrative error

Point-in-time reporting

Protection from application or user error

Snapshots are NOT a substitute for your backup and

recovery setup

You cannot roll forward

If either the database or the database snapshot is

corrupted, reverting from a snapshot is unlikely to

correct the problem

Query from snapshot current database

Database Snapshots

CREATE DATABASE AdventureWorks_dbss1800 ON( NAME = AdventureWorks2008_Data, FILENAME = 'C:\data\AdventureWorks_data_1800.ss' )AS SNAPSHOT OF AdventureWorks;GO

Database Snapshots

Database Snapshots

Snapshot vs. Backup vs. Detach

Snapshot• Only go back• SELECT statements

Backup• Rollback and Forward possible• Smaller

Detach database and copy• DB goes offline• Closes all connections

Database mirror

No special hardware

Configuring a Database Mirror

Configuring a Database Mirror

Easy to setup

Zero committed work lost Maximum one mirror per DB

Transparent client redirect

Virtually no distance limitations

No special hardware

Configuring a Database Mirror

Clients

Principal Server

Witness Server

Mirror Server

Configuring a Database Mirror

Configuring a Database Mirror

Clients

Witness Server

Mirror Server

Principal Server

Clients

Witness Server

Mirror Server

Principal Server

Configuring a Database Mirror

1. Principal

1. Take a full backup and a log backup as well2. Copy the full/log backups from Principal Instance to

Mirror instance

2. Mirror

1. Restore with NORECOVERY option the full backup2. Apply the log backup

Before you mirror your database

Using the Mirror Wizard

Configure End Point on the Principal

Configure End Point on the Mirror

Set the service accounts

Use NT AUTHORITY\NETWORK SERVICE

Mirror is configured

Warning about FQDN

Mirror Operating Modes

High Performance (asynchronous)

Commits are done on the principal and transferred to the mirror

High Safety (synchronous)

Commits are written to both databases

Database Mirroring Failover

What happens when something bad happens to our principal server…

You can make it failover to the mirror

This means that the two servers swap roles for the time being

Database Mirroring Monitor

Lets you view the status and history of your current mirrors

Thresholds

Might come in handy

Disable MirroringALTER DATABASE myDatabase SET PARTNER OFF

Put DB from "Recovering..." into available online modeRESTORE DATABASE myDatabase WITH RECOVERY

Partitioned tables

Partitioned Tables

Allows for maximum concurrency

Partitioned Table parallelism Improved a lot in SQL 2008

Archive older data into different filegroups

Partitioned Tables

SQL Server agent

Windows Service

Executes SQL Server jobs

Administrative tasks

SQL Server Agent (recap)

New credential system

Sits on Active Directory

Fine grained control of your jobs

Jobs can be run by proxies instead of user loginsPreviously to run cmd shell type functionality you needed a user in the administrator group which opened up security problems

SQL Agent Proxies

Online Index Operations

Online Index Operations

Table

Index Created

- Table is accessible for read and update- Non-clustered indexes are available during clustered index creation

- Table is accessible for read and update- Non-clustered indexes are available during clustered index creation

CREATE NONCLUSTERED INDEX IX_TextTable_MyKey

ON [TestTable] ([MyKey])

WITH (ONLINE = ON);

GO

Mirrored Backups

Mirrored Backup media

Mirror 2

Backup

Mirrored Backup media

Mirror 2

Mirror 1

Mirror 2

Mirror 1

Mirrored Backup media

Implementing Database Snapshots

Configuring a Database Mirror

Partitioned Tables

SQL Agent Proxies

Performing Online Index Operations

Mirrored Backups

Session Summary

High Availability Features

Database snapshots Mirrored backups Online Index Operations

Download from Course Materials Site (to copy/paste scripts) or type manually:

http://tinyurl.com/utssql2009

Session 3 Lab

• Free chats and webcasts

• List of newsgroups

• Microsoft community sites

• Community events and columns

• SQL Server user groups (www.sqlserver.org.au)

• www.microsoft.com/technet/community

Where Else Can I Get Help?

3 things…

PeterGfader@ssw.com.a

u

http://

peitor.blogspot.com

twitter.com/peitor

Thank You!

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