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cvandoes asked

Understanding failover cluster resource dependencies

Hi there I'm trying to make sense of the example from the article at https://support.microsoft.com/en-us/help/835185/failover-cluster-resource-dependencies-in-sql-server. I've pasted it here and my questions below. Example 1 - Default SQL Server failover cluster instance dependencies In this diagram, notice the following: Cluster Disk 1 has no required dependencies. IP Address: xxx.xxx.xxx.xxx has no required dependencies. IP Address: xxxx:xxxx:xx:xxxx:xxxx:xxxx:xxxx:xxxx has no required dependencies. Name: SOFTY dependencies are IP Address: xxxx:xxxx:xx:xxxx:xxxx:xxxx:xxxx:xxxx and IP Address: xxx.xxx.xxx.xxx. SQL Network Name (SOFTY) required dependencies are IP Address. SQL Server dependencies are Cluster Disk 1 and Name: SOFTY. SQL Server has no required dependencies. SQL Server Agent dependencies are SQL Server. SQL Server Agent has no required dependencies. Example 2 - SQL Server 2008 Analysis Services failover instance dependencies Can someone please explain the following: 1. In the above diagram what is the relevance of 'SQL Server Agent' being repeated as well as 'SQL Server', before the first '&'? 2. Then in the dependencies the following is stated: SQL Server Agent dependencies are SQL Server. SQL Server Agent has no required dependencies. Please explain the apparent contradiction of these these 2 statements. Thanks Craig
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DenisT answered
1 -- The reason it's repeated because the upper name represents the Resource Type and the bottom one its actual name. Since the default name is displayed, it looks like it was repeated twice. Please see the example below. I've renamed the default Cluster Resources. ![alt text][1] [1]: /storage/temp/4211-capture.jpg 2 - This means that SQL Server Agent does not require to have any dependencies to exist as a resource. Unlike for example, the Network Name cluster resource which has a dependency on the IP Address cluster resource. Meaning that if the IP Address cluster resource does not exist, the Network Name cluster resource cannot exist either. On the other hand, the SQL Server Agent cluster resource depends on the SQL Server cluster resource which means the only way it can be brought online if SQL Server comes online. HTH, Denis

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cvandoes answered
Denis, thank you very much for answering, much appreciated. So the difference is that the one line refers to the service, while the other refers to the cluster resource i.e. SQL Server Agent 'cluster resource' dependencies are SQL Server. SQL Server Agent 'service' has no required dependencies.
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DenisT avatar image DenisT commented ·
So look at this the way of a required dependency for a clustered resource allows for another clustered resource to exist. You can see the list here -- https://msdn.microsoft.com/en-us/library/aa372236(v=vs.85).aspx. If a resource has a required dependency on a resource that is missing in the cluster group, this resource cannot even exist without that resource. Where depend on resources are defined either manually or via SQL Server FCI install and can exist independently. Say, I have a disk that I don't SQL Server to depend on, I can easily exclude it and if this disk goes offline, it has no effect on SQL Server resource. The "depend on" resources are only responsible for a chain reaction of a resource going OFFLINE/ONLINE. Does it make sense? Sorry, I know it's confusing :)
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cvandoes avatar image cvandoes commented ·
Thanks Denis, I finally got it. :-)
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