Comments posted to this topic are about the item SQL Server 2012 Active/Active Cluster in Hyper-V
Unless there is a new 2012 feature that hasn't been well advertised, SQL Server does not do active/active clusters.
You have created two SQL instances which are active/passsive on different servers, i.e. multi-instance. But the instances are not active/active.
Also, there is little high-availability gained here because all the VMs are on the same host hardware. The use of an iscsi VM represents a single point of failure on the same hardware even if you put the cluster vms on separate hosts.
The article suggests routing SAN related disk IO over your virtual IP Network. If a million records were inserted in a table, the network would be flooded and any other users/processes would be hammered. That seems to me the biggest issue although it should be possible to configure the virtual iSCSI NIC to use a dedicated physical LAN.
The ideas in the article are intended to provoke thought and consideration of the possibilities offered by iSCSI SANs. Brent Ozar wrote an article recently about running SQL Server from network shares using trace flag 1807, Brents suggestion involves a lot less work to implement but perhaps, offers less resilience.
very good article, Paul!!!
Thanks very much Rfr, it was fun writing it.
Unless there is a new 2012 feature that hasn't been well advertised, SQL Server does not do active/active clusters. .....
the A/A cluster on SQL Server is possible when we talking about HA and not HP!! the scene designed by Paul, for each instance that is avail on node, you would configure half of resources server to SQL Server, i.e. the server has 8 Gb RAM and 8 cpus, then to SQL this instance would have 4 Gb RAM and 4 CPUs and same configuration for other node!!!
when one node fails the other takes full workload!!!
Now, the load balance of workload, users and databases between sql servers, is a job of DBA!!! where is possible configure A/A cluster for HA!!!
For HP, only Windows 2008 R2 HPC, when we want performance of both servers in specific task!
Great article, I am looking to build the same clustered environment using SQL 2008 R2/Win2008 R2 Server & virtual box.
This is also a good method.
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