How To Read Data from Mirror Database

This is continuation to our last post  i.e  how to configure mirroring in local system.

Let us have a look at post  implementation steps in mirroring .

Try to access Adventure works Database form Second Instance (Mirror server) you will get below error.

How can i read data from mirror database ,if i configure it as a report server !!

There is no straight way to read data from mirror database (log-shipping will supports secondary database as standby or read-only database  )But the internal mechanism of mirroring will not support this.

SQL Server 2005 introduced snapshot databases.Using this feature we can read data from Mirror Database.

USE [master]
GO
CREATE DATABASE [AdventureWorks_SNAPSHOT] ON
( NAME = N'AdventureWorks_Data', 
FILENAME = N'C:\Program Files (x86)\Microsoft SQL Server\MSSQL.1\MSSQL\Data\Adventureworks.SS' )
AS SNAPSHOT OF [AdventureWorks]
GO

Above command can be used to create Snapshot Database against Mirror Database.

Filename is path to the snapshot database  file.

After executing above command new snapshot database will create in mirror instance

This is pure read-only database and image of Adventure works Database (Mirror).Now we can read like any other read-only database.

Snapshot Databases will work in interesting manner ,we will have look into deep later.

You must have one doubt that how to create another mirror instance …

We canot create it in SQL 2005 or 2008 ,Up coming SQL version that is SQL 2001 (Denali) has that feature .i will cover this topic in future posts.

Bye for now..

How To Configure Database Mirrioring In Local System Without Domain

Today we are going to learn few Tips which are not documented in BOL.The reason i am writing this post is ,    Most of the learners may not have enough knowledge to build domain controller on virtual machines and failing to become familiar with High availability techniques like Database Mirroring.

As per BOL Mirroring require Fallowing prerequisites

1.Servers should be in same domain

2.SQL service accounts should be same domain accounts

All above points remain same ,treat as a best practice but there are situations, demands us to configure Mirroring in non-domain environment.

Here we start..

Pre implementation

1.We need Three SQL Server instances.

I have installed three SQL Server 2005 (ENT Evolution  Edition) instances and applied sp3.

Tip: Mirroring introduced in SQL 2005,  Only Enterprise and Developer Edition will support Database Mirroring

Mirroring functionality enabled from sp1 ,if you are using SQL 2005 RTM then you have to enable trace flag 1400.

2.All Instances are running on local machine ,using localsystem service account for SQL services.

3.All required protocols enabled for each instance.

Please have a look After completing above steps

Now I am going to implement Database Mirroring on Adventure-works database.

SQL_2005_ONE  As Principal Server

SQL_2005_TWO As Mirror server

SQL_2005_THREE As Witness Server

First Make sure that Adventureworks database is in Full recovery Model (It is must).

Now we need to take full backup of this database.

Perform Immediate Log backup ..

We have completed database full and log backup successfully.These backup files has to be restored on SQL_TWO_2005 Instance

Tip :We have to restore as same database name that is AdventureWorks.

Below are steps

Tip :Make sure to change restore location of files And Restore with NORECOVERY option

After above step we can able to see Adventureworks Database in Restoring mode

I am going to restore log backup file

After restoring log backup file ,database would be restoring mode

We are ready to start configuring database mirroring

Click on Configure Security

Database Mirroring Configuration wizard will open

I am going to configure Automatic fail-over (High availability mode),we need witness server for this

I am choosing “Yes” here in above step

Below Step is self explanatory

Here we are going to configure Principal server

Here Listener Port is 5022 (you can change it)

Endpoint, i am leaving it for wizard to configure with default values

Next step is configuring Mirror Instance

Next step is configuring Witness Instance

We are going to configure service accounts in mirroring

We are using all local system accounts in same machine ,so we can ignore this window

We have reached final window for configuring Mirroring

Final window showing that configuring endpoints with default values

All should be success

After successful configuration ,You will get   Start mirroring
window

I have selected Start Mirroring.But as usual got error message

SQL Server identified that we are not in Domain and giving error to start Mirroring secession

Now we have to troubleshoot this failure ,No wonder we are not in domain

Is that mean we cannot configure mirroring ? No

Here is the workaround to resolve this

I had verified Mycomputer properties

As we aware we are not in domain and Mycomputer is a member of  WORKGROUP

Click on  More Tab,You will get below window

I have empty box for Primary DNS suffix

I had enter Mydomain.com (you can choose your desired domain name fallowed by .com)

Click ok for all opened windows ,System will ask for Reboot.

After Rebooting the system ,verify your system name using cmd

Hmm !,My System name is remain same ,so no need to bother about SQL instances registration.

No need to bother about sp_dropserver and sp_addserver.

(You can ignore above step if you didn’t understand )

Let us start Mirror setup again

We have to do form the first step to start mirror window step

This time Mirrioring Started successfully !!

You can observe that server names having Mydomain.com and SQL Server treating that as Fully Qualified Domain Name.

We have configured Mirroring successfully in local machine with out domain

Now let me show you Some Interesting Things that are part of Mirroring

Our Principal and Mirror Databases showing their respective Role names in Managemenstudio

Now let me show you Automatic fail-over feature of mirroring

I had stopped Principal server service in configuration manager to simulate the failure of principle server

Now let us verify Mirrored Database  status

Please observe SQL_TWO_2005 was a Mirror Database, Now Became Principal automatically. This is a great feature of Mirroring (and latency also very less) as per Microsoft.

We can do this Fail over in different ways

First method using below command

Second Method

Database Properties >>Mirroring>>Failover

Now We will learn how to Monitor Mirroring Performance

The name implies the answer,Yes i am going to use Mirroring monitor

You will get mirroring monitor with empty records .Here we have to register principal or mirror server name

After registration we can see Principal,Mirror server Synchronization Status

History Tab will show more details

If require we can configure Warning Thresholds

As of now we have done Mirror configuration and monitoring.

This will be helpful to practice and getting familiar with New feature of  SQL server 2005 (Same steps applicable for SQL 2008 also)

There are multiple ways to configure mirroring in local machine or different domain environment   (using certificates is the one method)

But i am sure this is the simplest method among those.

Looking for your feedback to improve this blog

I will post more tips in future to simplify your SQL administration Learning

All The Best Friends.