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active/active vs active/passive cluster question


In my current situation, I have a active/passive situation, but I'm being pressured to turn it into a active/active under the perception that it will improve crunching power.

As I understood, Microsoft Clustering; it is a high-availability solution, not a load balancing one.

So with a active/active cluster, what are the benefits in a SQL environment?    It's not as if 2-nodes can share a single virtual SQL instance, so what would be the point of building a active/active cluster?

Thanks!

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Marketing_Insists
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Marketing_Insists
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DireOrbAntCommented:
First keep in mind that you only need one SQL license for an active/passive setup, two for an active/active one.
a/a is not load balancing in a round robin or NLB way... You have to balance the load yourself by creating two or more SQL instances.
The most basic setup will be two instances, one owned by each node. If you only have one database, or several interconnected ones, going to two instances might slow down joins over linked server.
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Marketing_InsistsAuthor Commented:
So I could increase crunching power by going active-active?

Is this safe to do? (a sql instance per node and a single database)
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Guy Hengel [angelIII / a3]Billing EngineerCommented:
active/active means that you have basically 2 databases. one on each node under normal conditions, but both on the same node in case of 1 node going down.
you will indeed, for normal conditions, have 2 times the power, but you have to be aware (and test), that in case 1 node goes down (or has to go down for maintenance), that the 2 database share only 1 node's power.

>Is this safe to do? (a sql instance per node and a single database)
correct statement is: you have 2 sql instances on each node. one active and one passive in normal conditions.
correctly, the naming of the 2-node-cluster would hence be active+passive/passive+active . active/active is shorter :)

you can use the 2 databases to share load. however, the clustering will not help you natively, you have to do that via the application code, for example a web server farm in case of a web application.
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DireOrbAntCommented:
>>active/active means that you have basically 2 databases.
I just want to make apotential correction. It means you have 2 INSTANCES. They might each have one DB, thus 2 DBs :)
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Marketing_InsistsAuthor Commented:
So would you say that active/active is more of a hardware conservation measure?
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