March 31, 2009 at 3:52 am
I am bignner for SQL 2005 so i want to details for topic ,that what is the advantage And why we use for this ?
Thanks
March 31, 2009 at 4:15 am
Mirroring is, like its name, a realtime copy of a database on another server. Where clustering is a mechanism for catching a complete servercrash, with mirroring you'll have the possibility to have an updated copy of a specific database.
There are 3 levels of protection in mirroring. With the highest level of security, you'll have the option of an automatic "failover" to your mirrored database in case of some problems on the source database.
Keep in mind that you can't use the mirrored database directly, it's in a recovery mode (replaying all the transactions from the source server). but you can create a snapshot of this database and use it for reporting purposes (your managers like that 🙂 )
Search for "mssql" and "mirroring" on the www for more articles!
Wilfred
The best things in life are the simple things
March 31, 2009 at 7:27 am
SQL Server provides a set of high availability methods that the users can use to achieve fault tolerance and to prevent server outages and data loss. The selection of the high availability method depends on various factors. Some DBAs need the servers to be available 24/7, while others can afford an outage of a couple of hours. Cost also plays a role in the selection. For example, Clustering is an expensive high availability method when compared to Database Mirroring, but it allows the user to failover immediately.
The following high availability features are available with the Enterprise edition:
* Failover Clustering
* Multiple Instances(up to 50)
* Log shipping
* Database Snapshots
* Database Mirroring
Database Mirroring is a primarily software solution for increasing database availability. Mirroring is implemented on a per-database basis. Mirroring works only with full recovery model. Database mirroring is available in the Enterprise edition and in the Standard edition. The user can mirror only the user databases.
Mirroring allows the user to create an exact copy of a database on a different server. The mirrored database must reside on different instance of SQL Server Database engine. Microsoft fully supports database mirroring with SQL Server 2005 SP1 onwards. For the RTM release (prior to SP1), Microsoft support services will not support databases or applications that use database mirroring. The database mirroring feature should not be used in production environments. Prior to SP1, database mirroring is disabled by default, but can be enabled for evaluation purposes by using trace flag 1400. The following T-SQL statement can be used to achieve this:
DBCC TRACEON(1400)
Benefits of Database Mirroring:
1.Implementing database mirroring is relatively easy.It does not require any additional hardware in terms of clustering support.So it proves to be a cheaper implemetation instead of cluserting a database.
2. Database mirroring provides complete or nearly complete redundancy of the data, depending on the operating modes.
3.It increases the availability of the database.
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March 31, 2009 at 7:28 am
http://msdn.microsoft.com/en-us/library/5h52hef8.aspx
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March 31, 2009 at 8:08 am
143.manvendra (3/31/2009)
I am bignner for SQL 2005 so i want to details for topic
BOL is your "best mate"
,that what is the advantage And why we use for this ?
Thanks
The advantages: Automatic Failover, We use this to achieve High Availability.
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