Showing posts with label High Availability. Show all posts
Showing posts with label High Availability. Show all posts

Monday, July 16, 2012

Implementation of Mirror Database Using SSMS

Implementation of mirror database consist of special set of step that enables the SQL to perform mirroring.
In this post I would be discussing the Mirror implementation from SSMS which is easy and in our next post we discuss about T SQL implementation.

Steps:


1. Take full full back up of principal database using right click -)Task-)backup-) full
2.Take transaction log back up of principal database using right click -)Task-)backup-) transaction log
3. Open Mirror Server right click  Mirror  database-)Task-)restore-) full
4. Open Mirror Server right click  Mirror  database-)Task-)restore-) transaction logs
5.Open Principal server go Task-) Mirror -) configure-)Set the principal-)Set the mirror-)Set the witness (if you want automatic fail over to mirror database in case principal database die)

And yes above Five steps are enough to start your mirroring using SSMS.
In our post we discuss about T -SQL implementation of mirroring

Saturday, July 14, 2012

Database Mirroring


Database Mirroring

Mirroring was intorduce in 2005 by Microsoft. It is a low cost low maintenance solution when I say low maintenance it only means it has degree less complex than the cluster. In Mirroring, Principal database is duplicated exactly to a Mirror which is clear from its name.

Let consider pros and cons for which some people like mirroring and some don't.

Pros:
1. It easy to implement.
2. It can ensure no data loss (if using High Safety mode)
3.It provides a secure copy of database separate from the production so if production goes down Mirror database kicks in immediately without using time for manual restoration.
4.it provide three modes of operations. Asynchronous , Synchronous without witness ,Synchronous with witness.

Cons:
Most people think Mirror Server is actually a waste of resource. Reason because it waiting for principal server to die malfunction  or gone for maintenance and then it can start. It something more then standby server and database.

Asynchronous : Principal database commit data without waiting for mirror database to commit. Data loss chance present.

Synchronous without witness : Principal database does not commit data before the mirror database. Therefore principal database waits for mirror database to commit first. No Data loss. Manual fail over to Mirror Database

Synchronous with witness:Principal database does not commit data before the mirror database. Therefore principal database waits for mirror database to commit first. No Data loss. Automatic fail over to Mirror Database.

Implementation of mirror Server will be discussed in the next and above will be linked with the post.

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