This monitor checks if database mirror witness is accessible.
Knowledge Base article:
Summary
This monitor checks the status of the database mirroring witness as reported by Microsoft® SQL Server™. This is performed by running a query against the master database of the SQL Server instance and returning the state of the database mirroring witness. If you receive an alert from this monitor, an action is required in order to bring the database mirroring witness back to an operational state.
Causes
Unhealthy state indicates that the SQL Server™ database mirroring witness is currently unavailable. All states except CONNECTED and NO-WITNESS will cause Unhealthy state. The possible states are detailed below:
Mirroring Witness State
Description
MOM Health State
CONNECTED
This is normal operational state. Mirroring Partner can access the Witness server.
HEALTHY
NO-WITNESS
This state indicates that there is no Witness specified for the mirroring session. It is normal operational state for High-Performance Mode and High-Safety Mode Without Automatic Failover.
HEALTHY
UNKNOWN
There are some issues with connection between Mirroring Partner and Witness server.
WARNING
DISCONNECTED
There is no connection between Mirroring Partner and Witness server.
CRITICAL
Resolutions
To resolve the issue try the following:
Make sure mirroring configuration is complete and mirroring process is up and running.
Check physical link between Mirroring Partner and Witness server.
Configure firewall rules on both servers according to endpoints configuration.
Overridable Parameters
Name
Description
Default Value
Alert Priority
Defines Alert Priority.
Normal
Alert Severity
Defines Alert Severity.
MatchMonitorHealth
Enabled
Enables or disables the workflow.
Yes
Generates Alerts
Defines whether the workflow generates an Alert.
Yes
Interval (seconds)
The recurring interval of time in seconds in which to run the workflow.
900
Synchronization Time
The synchronization time specified by using a 24-hour format. May be omitted.
Timeout (seconds)
Specifies the time the workflow is allowed to run before being closed and marked as failed.
Dim GetWitnessStatusQuery
GetWitnessStatusQuery = "SELECT " &_
" d.name, " &_
" CASE WHEN dm.mirroring_witness_name = '' THEN 'NO-WITNESS' ELSE ISNULL(dm.mirroring_witness_state_desc, 'UNKNOWN') END " &_
" FROM sys.databases d " &_
" INNER JOIN sys.database_mirroring dm ON dm.database_id = d.database_id " &_
" WHERE dm.mirroring_guid IS NOT NULL"
Call GetWitnessAccessibility()
Sub GetWitnessAccessibility()
If WScript.Arguments.Count = 4 Then
Dim oBag
Set oBag = oAPI.CreatePropertyBag()
Dim state, serviceName
serviceName = GetSQLServiceName(WScript.Arguments(2))
state = GetServiceState(WScript.Arguments(1), serviceName)
If (state <> "Running") And (state <> "Unknown") Then
Call oAPI.Return(oBag)
WScript.Quit()
End If
Dim nResult
nResult = WitnessAccessibility(WScript.Arguments(0), oBag, WScript.Arguments(1), WScript.Arguments(2), WScript.Arguments(3))
On Error Resume Next
Call GlobalErrorListToEventLog()
Call oAPI.Return(oBag)
Else
On Error Resume Next
Call GlobalErrorListToEventLog()
Wscript.Quit()
End If
End Sub
Function WitnessAccessibility(ByVal sSQLConnectionString, ByRef oBag, ByVal sComputerName, ByVal sInstanceName, ByVal sTcpPort)
Dim e
Set e = New Error
Dim cnADOConnection
Set cnADOConnection = SmartConnectWithoutSQLADODB(sSQLConnectionString, sTcpPort, sComputerName, sInstanceName, "master")
if cnADOConnection Is Nothing Then
WitnessAccessibility = SQL_MONITORING_CONNECT_FAILURE
Exit Function
End If
Dim oResults
e.Clear
On Error Resume Next
Set oResults = cnADOConnection.Execute(GetWitnessStatusQuery)
e.Save
On Error Goto 0
If e.Number <> 0 Then
WitnessAccessibility = SQL_MONITORING_QUERY_FAILURE
ThrowScriptErrorNoAbort "Query execution failed for '" & sSQLConnectionString & "' SQL Server", e
If (oResults <> null) Then oResults.Close
cnADOConnection.Close
Exit Function
End If
Do While Not oResults.EOF
Call oBag.AddValue(oResults(0) & "-State", CStr(oResults(1)))
oResults.MoveNext
Loop
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