Hey guys i am learning about MS SQL-Server clustering instances. I am wondering if you could add a cluster on a existing instance of SQL server 2012. I mean is it the whole point of clustered instances: to create a new instance that supports disaster recovery?
Asked
Active
Viewed 141 times
2
Has QUIT--Anony-Mousse
- 76,138
- 12
- 138
- 194
Hamza Rashid
- 21
- 1
-
I think clustering is a technology that allows one server to take the tasks and responsibilities of failed server – bmsqldev Jan 14 '16 at 05:26
1 Answers
0
I have no experience in clustering a SQL Server (I'm no DBA) so all I can give is a link (brentozar.com - An Introduction to SQL Server Clusters) with a good read.
The main things to take away from this excellent post, written by Kendra Little, and I quote:
Key Concept: A Windows Failover Cluster uses shared storage– typically, this shared storage is on a SAN. When a SQL Server instance is installed on the cluster, system and user databases are required to be on the shared storage. That allows the cluster to move the SQL instance to any server (or “node”) in the cluster whenever you request, or if one of the nodes is having a problem. There is only one copy of the data, but the network name and SQL Server service for the instance can be made active from any cluster node.
Translation: A failover cluster basically gives you the ability to have all the data for a SQL Server instance installed in something like a share that can be accessed from different servers. It will always have the same instance name, SQL Agent jobs, Linked Servers and Logins wherever you bring it up. You can even make it always use the same IPAddress and port– so no users of the SQL Server have to know where it is at any given time.
The link has a beautiful description of a use-case with 2 simple images but I don't want to incorporate the whole post in here. If the quote doesn't make things clear, surf to the link.
