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jchrist79
Starting Member
7 Posts |
 Posted - 2010-07-14 : 22:32:56
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| Does anyone know whether two node active/active clustering is supported with Sql Server 2008? I have found some forum discussions which suggest that it is but I havent seen any documentation from microsoft which says that it is.--------------------Cheers,James |
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jeffw8713
Aged Yak Warrior
819 Posts |
Posted - 2010-07-14 : 23:18:43
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| What do you consider active/active? In Microsoft terms, you can have a multi-instance cluster where any node can host any number of separate SQL Server instances. Only a single node can host and access the databases for an instance at one time. This is known as HA clustering.If you are looking for a load balancing type of clustering - that is not supported for SQL Server. |
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jchrist79
Starting Member
7 Posts |
Posted - 2010-07-15 : 00:31:05
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Thanks for your reply Jeff,I mean having multiple instances on each node. i.e. instance A and instance B on node 1 and instance A and instance B on node 2. The normal situation would be that instance A on node 1 is active and instance B inactive and on node 2 instance A is inactive and instance B is active. If instance A on node 1 failed over then instance A on node 2 would become active. Its not load balancing but in this situation at least you dont have both instances on one node active in normal running conditions...only when there is a failover. Is this scenario possible to achieve using SQL Server 2008 Standard Edition?Also are you aware of any memory/virtual memory issues under such a scenario?quote:
Originally posted by jeffw8713
What do you consider active/active? In Microsoft terms, you can have a multi-instance cluster where any node can host any number of separate SQL Server instances. Only a single node can host and access the databases for an instance at one time. This is known as HA clustering.If you are looking for a load balancing type of clustering - that is not supported for SQL Server.
--------------------Cheers,James |
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jeffw8713
Aged Yak Warrior
819 Posts |
Posted - 2010-07-15 : 19:05:50
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| You would only have two instances installed on the cluster. Instance A would be installed into the cluster and the available nodes for that instance would be node1 and node2. Instance B would be installed the same way.You would host InstanceA on node1, Instance B on node 2 - and be able to fail either instance over to the other node as needed using Cluster Administrator. You have to have separate resources available (drives) for each instance - and each instance must be in it's own cluster group (with it's own Virtual Name and IP Address).In a multi-instance configuration, you have to be aware of how much memory each instance is going to use and configure the max memory for that instance. You might also want to configure the min memory - to make sure each instance has enough memory to support normal operations. You should not set the min memory = max memory, as that can cause problems for SQL Server.You need to make sure that you don't allocate more memory to the instances than is available to each server in the cluster, minus the memory for the OS. For example, if you have 32GB of memory - you want to leave at least 4GB of memory (possibly more) to the OS. That would leave 28GB of memory available which could be spread evenly between each instance, or one could have more - the other less. This will insure you have enough resources available on a single node to support all instances if one of the nodes crashes. |
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jen
Master Smack Fu Yak Hacker
4110 Posts |
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Active/Active Clustering Sql 2008 Standard Edition