# Friday, 15 April 2011

In a clustered environment, it may not always be obvious what node SQL Server has been running on. Most logging is done based on the network name of the resource group, or the instance name of the virtual server. Still it is logged once in the Windows Application Event Log and the SQL Server Error Log each, though the “memory” of those sources is likely limited by configuration; size and overwrite settings of the application log and number of error logs (maximum 99) for the SQL Server Error log.

In the Windows Application Event Log, the EventID 17664 is of interest (verify the source is an SQL Server instance). Event Log filtering is relative straight forward and turns up an event like this.

EventMessageNodeSQLServer

Figure Event Properties; 1 = Instance name, 2 = Network name of the resource group, 3 = Computer name of the cluster node, 4 = Binary code containing network name\instance name

In case of the SQL Server Error Logs, the thing of interest is the message;

The NETBIOS name of the local node that is running the server is 'computername'. This is an informational message only; no user action is required.

Parsing the files might be the easiest from SQL Server with the xp_readerrorlog. Unfortunately error handling surrounding eXtended stored Procedures is limited. Using the script below, the last result set shows the node where a clustered SQL Server was started on.


SET
NOCOUNT ON
DECLARE
@iteration
int
DECLARE
@log_events table ([LogDate] datetime, [ProcessInfo] nvarchar(20), [Text] nvarchar(max), [Iteration] int
)
SELECT @iteration = 0
-- Set to current error log
WHILE @iteration <
100
    BEGIN
    BEGIN
TRY
        -- EXECUTE the XP without INSERT to trip the error.
        -- XP error is handled poorly, but it is even worse
        -- when it occurs on the insert from executing an XP.
        EXEC xp_readerrorlog @p1 = @iteration, @p2 = 1, @p3 = 'NETBIOS name'
;
        INSERT @log_events ([LogDate], [ProcessInfo], [Text]
)
            EXEC xp_readerrorlog @p1 = @iteration, @p2 = 1, @p3 = 'NETBIOS name'
;
        UPDATE
@log_events
            SET [Iteration] =
@iteration
       
    WHERE [Iteration] IS
NULL;
        SELECT @iteration = @iteration + 1
;
   
END
TRY
    BEGIN
CATCH
        SELECT
@iteration = @iteration + 1
;
    END
CATCH
    END
SELECT
[Iteration],
[LogDate]
   
    , CAST(SUBSTRING(

           
SUBSTRING([Text]

            ,
LEN('The NETBIOS name of the local node that is running the server is ''') + 1
           
,16
-- Max length NETBIOS name is 16 char (15 actually).
   
    ), 1, CHARINDEX('''', SUBSTRING
(
            [Text]
           
,LEN('The NETBIOS name of the local node that is running the server is ''') +
1
           
,16
-- Max length NETBIOS name is 16 char (15 actually).
   
    )
    )
- 1) AS varchar(16)) AS
'NodeName'
FROM
@log_events
WHERE [Text] LIKE
'The NETBIOS name of the local node that is running the server is %'

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