In SQL Server 2012 onwards, the cluster health check detection logic has been enhanced. Instead of the traditional pull mechanism of the cluster (IsAlive and LooksAlive), SQL Server (version 2012 onwards) uses a push mechanism to detect the health of the SQL instance. This is done by special stored procedure called sp_server_diagnostics. We should remember that the failover mechanism for the AlwaysOn FCI and the AlwaysOn Availability Groups is same.
SQL SERVER – AlwaysOn Join Error – Msg 1408, Level 16 – The Remote Copy of Database “SQLAUTH” is Not Recovered Far Enough to Enable Database Mirroring or to Join it to the Availability Group
I do provide consultancy services for deployments, including AlwaysOn availability group deployments. AlwaysOn Join Error.
SQL SERVER – FIX: Msg 35250, Level 16, State 7 – The Connection to the Primary Replica is Not Active. The Command Cannot be Processed
Along with my performance consulting, I also assist many clients in fixing some quick issue. You can refer for various consulting services which I provide. This blog is an outcome of one such engagement where the client has deployed standalone SQL Server on two machines, created windows cluster between them and wanted to then use AlwaysOn availability group feature. This blog is about Primary Replica not being active.
SQL SERVER – The Lease between Availability Group ‘PRODAG’ and the Windows Server Failover Cluster has Expired
This is one of the common errors I have seen while working with customers who are using SQL Server AlwaysOn availability groups. Once this error comes, the resource in the cluster goes to failed state and in SQL Server Management Studio, we should be an availability group in resolving state. Resolving state essentially means that the role of availability group is neither primary nor secondary.
SQL SERVER – AlwaysOn Listener Error – The WSFC Cluster Could Not Bring the Network Name Resource With DNS Name ‘DNS name’ Online
I can tell you how many times I have heard about this error. This can appear in any of the situation where SQL needs to create a cluster network name resource in the WSFC Cluster. Here are the two situations I can think of:
Installing SQL Server Failover Cluster instance.
Creating listener in the AlwaysOn availability group.
SQL SERVER – Availability Group Missing or Deleted Automatically?
As a part of my passion, I try to help people in fixing simple issues and explain the behavior by looking at logs. Here is an email from my friend about Availability Group Missing or Deleted Automatically.
SQL SERVER – FIX : Msg 35295, Level 16 – Log Backup For Database ‘DBName’ on a Secondary Replica Failed
Once, while doing a load testing with my client, I was shown below error while taking log backups on secondary replica.
Msg 35295, Level 16, State 1, Line 1
Log backup for database “MyAppDB” on a secondary replica failed because the last backup LSN (0x0016ff11:00032258:0001) from the primary database is greater than the current local redo LSN (0x0016ffec:0006ee28:0001). No log records need to be backed up at this time. Retry the log-backup operation later.
Msg 3013, Level 16, State 1, Line 1
BACKUP LOG is terminating abnormally.