SQL Server always on , one of the nodes down

Question

hi all,

we had high availability always on clustering set up

one of the nodes could not be booted up, so it is down.

ever since the cluster has only one node.

but there are errors in the windows log and informational messages in the sql server logs as seen below.

what can be done to "clean" both the sql server and windows so the node ALa-SQL-01 is not seen anymore

Always On Availability Groups: Local Windows Server Failover Clustering node started. This is an informational message only. No user action is required.

Answer 1

what can be done to "clean" both the sql server and windows so the node ALa-SQL-01 is not seen anymore

SQL Server is pretty simple, remove the replica from the availability group. In fact, if you haven't already completed this then your log is being held and will continue to grow unabated until it hits the specified limit and your database stop functioning.

The Windows side would be to evict the node from the cluster. You may also have to manually clean up active directory of any computer accounts.

ever since the cluster has only one node.

Then you don't have any high availability, which is a problem if you want HA.

Answer 2

Hi @NeophyteSQL ,

SQL server AG is based on WSFC. Deploying Always On availability groups for HA on Windows requires a Windows Server Failover Cluster(WSFC). Each availability replica of a given availability group must reside on a different node of the same WSFC. You had to fix the windows failover cluster issue firstly, then fix the AG issue.

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Answer 3

For some reason, the broken cluster node cannot be evicted.

what happens when cluster is destroyed. (destroy cluster option)

does the sql cluster name still hold good, or do the applications need to connect to the stand alone instance name.