In certain situations, an MSSQL Always-ON cluster fails on creation time. This article provides information and the steps required to resolve the cluster fails and recreate the cluster creation as expected.
- ScaleArc all versions, MSSQL cluster with Always-ON
- Deleted or orphaned entries in an internal MSSQL table holding Always-ON cluster configuration.
Verify that the entries on the corresponding cluster to be created are present.
- It is possible that the AWO cluster corresponding to the listener is not reflecting the entries in
sys.dm_hadr_instance_node_mapcorresponding to your cluster.
- This is due to deleted AGs (Availability Groups) listing on the registry.
- ScaleArc runs several queries against the VNN server to discover the configuration options for AGswithin the Always-On setup.
- One of these queries is:
- This query can have an empty result set if there are any deleted Availability Groups listing within the registry on the server that is currently running the VNN.
NOTE: Although all members of the AG should be checked for the same registry entry.
Clear the registry by following the steps below to solve this:
regediton the SQL Server.
- Browse to
- Backup the registry key.
- Remove any deleted records.
- Verify that running the query results for the
ag_resource_idcorresponding to the
returns for example
WHERE ag_resource_id ='be697968-d6ef-4fe6-a9e3-4c278c8bea4c';
- If rows returned exceed 0, recreate the cluster within ScaleArc.
Recreate the Always-ON cluster, it will succeed fetching the database information and it will allow you to finish the cluster creation as expected.