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September 28, 2017

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AlwaysON – Unable to access the ‘JB1’ database because no online secondary replicas are enabled for read-only access. (Microsoft SQL Server, Error: 982)

Environment

Blog29_1

-> The Application makes a connection to the Database JB1 with ApplicationIntent=ReadOnly and receives below message,

Unable to access the ‘JB1’ database because no online secondary replicas are enabled for read-only access. Check the availability group configuration to verify that at least one secondary replica is configured for read-only access. Wait for an enabled replica to come online, and retry your read-only operation.
Changed database context to ‘JB1’. (Microsoft SQL Server, Error: 982)

-> The message indicates that there are no active Read-Only partners. When checked further it is clear that Server JBSERVER2 and JBSERVER3 were down.

-> We were advised that the Servers JBSERVER2 and JBSERVER3 will not be up for next 6 Hours. Now the Application team doesn’t want to change their connection string by dropping ApplicationIntent=ReadOnly and wanted us to make sure that the primary accepts Read connections.

-> The Alwayson Availability group setting is as below,

Blog35_1.PNG

-> We changed the setting “Connections in Primary Role” from “Allow read/write connecions” to “Allow all connections” as below,

Blog35_2.PNG

-> The Application started connecting to the Primary Replica even with ApplicationIntent=ReadOnly.

-> This now brings up the question, why can’t we have the setting “Connections in Primary Role” set to “Allow all connections” instead of “Allow read/write connecions”. “Allow all connections”  can be an issue as Connections where the Application Intent is set to ReadOnly are not disallowed on the Primary Replica anymore. With this setting in place the read workloads may execute on both Primary and the secondary, If server JBSERVER2 which is on the same data centre as the PRIMARY goes down and we have intermittent network issues between DataCenters which makes JBSERVER3 to be offline Intermittently for JBSERVER1. So the Read workload might run on both JBSERVER1 and JBSERVER3.

Thank You,
Vivek Janakiraman

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