Hi,
We are currently using SQL 2014 Always-On . We have cluster setup with three nodes , Node 1 and Node 2 have setup with Automatic failover , Node 3 is setup with manual failover. Node 1 is the primary node, 2 and 3 are secondary
Occasionally Sudden Automatic Failover happen to Node 2 which becomes the primary node. Node 1 becomes out of Sync and we have to restart the SQL Service on Node 1 to bring it back in sync.
We always check that at the time of these sudden failovers to see if there's any any particular network event ( like a switch down or loss of power), but usually the answer is that the network infrastructure is running normally.. Node 1 is a physical server and the server is up and running when this failover happen. We can confirm that because we can remote desktop to the machine of Node 1.
Not sure what's causing this. Below are some of the SQL Server log entries at the time of this failover:
1st message is usually this :
Message
A connection timeout has occurred on a previously established connection to availability replica 'Node3' with id [6C63DEA5-35E7-4C9A-A8B3-BE40752B1608]. Either a networking or a firewall issue exists or the availability replica has transitioned to the
resolving role.
two minutes later this message:
The local availability replica of availability group 'SynergyDB' is in a failed state. The replica failed to read or update the persisted configuration data (SQL Server error: 41029). To recover from this failure, either restart the local Windows
Server Failover Clustering (WSFC) service or restart the local instance of SQL Server.
Message in the cluster events from the failover cluster manager:
Cluster node 'NODE01' was removed from the active failover cluster membership. The Cluster service on this node may have stopped. This could also be due to the node having lost communication with other active nodes in the failover cluster. Run the Validate a Configuration wizard to check your network configuration. If the condition persists, check for hardware or software errors related to the network adapters on this node. Also check for failures in any other network components to which the node is connected such as hubs, switches, or bridges.
SQL 2014 Build #:12.0.4100.1
OS:Microsoft Windows Server 2012 R2 Standard Edition
Any help is much appreciated.Thanks,