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SQL Server Cluster LooksAlive and IsAlive Check


Windows Cluster Service use the “heartbeat” process to check whether each node is alive at both the OS level and SQL Server level. Heartbeat signals works on UDP.

Microsoft Windows Cluster service perform 2 health checks to perform node & resource availability check.

LooksAlive Health Check

1) LooksAlive is a quick lightweight health check

2) Run at interval of 5 Seconds

3) Does not impact performance but does not perform a thorough check

4) The check will succeed if the service appears to be running even though it might not be operational

5) If Fails calls “IsAlive” health check

6) Polling interval can be changed by adjusting LooksAlivePollInterval property of Cluster service

IsAlive Health Check

1) Run at interval of each 60 Second

2) Perform more detail check then LooksAlive

3) Run @@SERVERNAME to ensure that SQL Server is responding to queries

4) Does not ensure that all user databases are operational

5) Retired 5 times & then try to reconnect SQL Server

6) If all 5 retry fails, the SQL Server resource fails & Windows Cluster service will try to bring it online on other node as per configuration

7) Polling interval can be changed by adjusting IsAlivePollInterval property of Cluster service

Reference : Rohit Garg (http://mssqlfun.com/)

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Creation & Deletion of Database Snapshot by SQL Agent Job


Some days back, I received one query on my facebook page that user want to create Database Snapshot frequently & want to delete the oldest with same frequency. Quite interesting scenario. I did not go in deep why he has such requirement but I am clear that It can be done very easily.

So let’s do it. I have setup 2 scripts one for creation of snapshot & another is for deletion of snapshot. We can schedule a SQL agent jobs with 2 steps using these scripts.

Step 1 :-

DECLARE @CREATE_SS VARCHAR(MAX)

DECLARE @DT VARCHAR(100)

SET @DT = REPLACE(REPLACE(REPLACE(CONVERT(VARCHAR,GETDATE(),120),’-‘,’_’),’ ‘,’_’),':’,’_’)

SET @CREATE_SS =

‘CREATE DATABASE TEST_’+@DT+’ ON

( NAME = TEST, FILENAME =

”C:\TEST_’+@DT+’.SS” )

AS SNAPSHOT OF TEST’

EXEC (@CREATE_SS)

Step 2 :-

IF(SELECT COUNT(*) FROM SYS.DATABASES WHERE SOURCE_DATABASE_ID = DB_ID(‘TEST’))>1

BEGIN

DECLARE @DROP_SS VARCHAR(MAX)

DECLARE @SS_NAME VARCHAR(100)

SELECT TOP 1 @SS_NAME = NAME FROM SYS.DATABASES WHERE SOURCE_DATABASE_ID = DB_ID(‘TEST’)

ORDER BY CREATE_DATE ASC

SET @DROP_SS = ‘DROP DATABASE ‘+ @SS_NAME

EXEC (@DROP_SS)

END

Reference : Rohit Garg (http://mssqlfun.com/)

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SQL Server 2005 || Database backup failed because Full Text catalog files are OFFLINE


Error : Database backup is getting fail with below reason.

The backup of full-text catalog ‘FullTextCatalog’ is not permitted because it is not online. Check errorlog file for the reason that full-text catalog becomes offline and bring it online. Or BACKUP can be performed by using the FILEGROUP or FILE clauses to restrict the selection to include only online data.

Cause : This behavior occurs because a full-text catalog in the database is not online. To perform a full backup, SQL Server 2005 requires all the database files and full-text catalogs in the database to be online.

Possible Reason : The database is attached from somewhere. However, you specify the incorrect location for the full-text catalog folder during the attachment.

Solution 1 (If FTS files are available but SQL server showing offline):

1. Locate the folder that contains the files for the problematic full-text catalog.

2. Run the ALTER DATABASE statement. Specify in the statement the correct location for the full-text catalog.

3. Rebuild the problematic full-text catalog in the database.

4. Perform a full backup of the database in SQL Server 2005 again.

Solution 2 (If FTS files are not available):

1. Detach database & attach again with all MDF, NDF, LDF & FTS files.

Web Reference :

1) http://support.microsoft.com/kb/923355

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Reference : Rohit Garg (http://mssqlfun.com/)

Renaming or Changing SQL Server Cluster Instance


Renaming or Changing SQL Server cluster instance process is bit different from renaming a stand-alone instance.

Refer : Rename or Change SQL Server Standalone Default Instance http://mssqlfun.com/2014/06/30/rename-or-change-sql-server-standalone-default-instance/)

Refer : Rename or Change SQL Server Standalone Named Instance (http://mssqlfun.com/2014/07/29/rename-or-change-sql-server-standalone-named-instance/)

The name of the virtual server is always the same as the name of the SQL Network Name (the SQL Virtual Server Network Name). You can change the name of the virtual server, you cannot change the instance name like in the case of standalone named instance. You can change a virtual SQL server named SQLServerinstance1 to some other name, such as SQLServerNewinstance1, but the instance part of the name, instance1, will remain unchanged.

Rename a virtual server :-

1. Using Cluster Administrator, change the SQL Network Name or SQL Server DNS Name to the new name.

2. Take the network name resource offline. This takes the SQL Server resource and other dependent resources offline as well.

3. Bring the SQL Server resource back online.

Verify the Renaming Operation :-

1) Using @@ServerName

2) Using sys.servers

Minimize network propagation delay :-

ipconfig /flushdns

ipconfig /registerdns

nbtstat –RR

You are done ! You should ask your application teams to reconnect with new Name or if they are using IP address then no changes required.

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Reference : Rohit Garg (http://mssqlfun.com/)

How to change TempDB system Database files location?


Steps to change TempDB system Database files location :-

1) Check current file location of TempDB

Exec SP_helpDB TempDB

You can use below query as well for file location details.

SELECT name, physical_name AS CurrentLocation, state_desc

FROM sys.master_files

WHERE database_id = DB_ID(‘TempDB’);

2) Execute Alter Database command with Modify Filename option on Tempdb System Database

USE master

GO

ALTER DATABASE tempdb

MODIFY FILE (NAME = tempdev, FILENAME = ‘E:\SQL2K5_1\TempDB\tempdb.mdf’)

GO

ALTER DATABASE tempdb

MODIFY FILE (NAME = templog, FILENAME = ‘E:\SQL2K5_1\TempDB\templog.ldf’)

OUTPUT :-

The file “tempdev” has been modified in the system catalog. The new path will be used the next time the database is started.

The file “templog” has been modified in the system catalog. The new path will be used the next time the database is started.

3) Restart SQL Server (TempDB automatically recreate from scratch every time SQL Server restart. To change files location, Just need to alter the file location done in step 2 & after restart SQL server will create files at new mentioned location)

4) Check file location of TempDB – After restart

5) Delete Old TempDB files from previous location to clear disk space from unused & junk files

Note : TempDB file location cannot change with deattach attach method. TempDB availability is mandatory for SQL server to come online.

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Reference : Rohit Garg (http://mssqlfun.com/)

Add Node to Windows Server 2008 Cluster


Steps : Add Node to Windows Server 2008 Cluster

1) Open Cluster Administration wizard > Right click on Windows Cluster & select Add Node

2) Add Node Wizard appears, Click Next to start

3) Browse Node to add, We select Node 3 to add

4) Select if you want to validate cluster settings or not & click Next

Note : Validation cluster settings is recommended

5) Validation a Configuration wizard will come, Click Next to start validation

6) Select type of test & click Next

7) Click Next to start Validation

8) Validation completed successfully(Warning to re configure quorum comes, we can ignore that), Click Finish to continue add node process

9) Click Next to start add process

10) Add node in process

11) Node 3 successfully added to cluster

Note : We need to reconfigure quorum to clear this warning.

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Reference : Rohit Garg (http://mssqlfun.com/)

Cumulative Update – 12 for SQL Server 2008 R2 Service Pack 2 Is Now Available !


The 12th cumulative update release for SQL Server 2008 R2 Service Pack 2 is now available for download at the Microsoft Support site. Cumulative Update 12 contains all the hotfixes released since the initial release of SQL Server 2008 R2 SP2.

Those who are facing severe issues with their environment, they can plan to test CU12 in test environment & then move to Production after satisfactory results.

To other, I suggest to wait for SP3 final release to deploy on your production environment, to have consolidate build.

KB Article For CU12 of SQL Server 2008 R2 SP2

Previous Cumulative Update KB Articles:

· CU#11 KB Article: http://support.microsoft.com/kb/2926028

· CU#10 KB Article: http://support.microsoft.com/kb/2908087

· CU#9 KB Article: http://support.microsoft.com/kb/2887606

· CU#8 KB Article: http://support.microsoft.com/kb/2871401

· CU#7 KB Article: http://support.microsoft.com/kb/2844090

· CU#6 KB Article: http://support.microsoft.com/kb/2830140

· CU#5 KB Article: http://support.microsoft.com/kb/2797460

· CU#4 KB Article: http://support.microsoft.com/kb/2777358

· CU#3 KB Article: http://support.microsoft.com/kb/2754552

· CU#2 KB Article: http://support.microsoft.com/kb/2740411

· CU#1 KB Article: http://support.microsoft.com/kb/2720425

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Reference : Rohit Garg (http://mssqlfun.com/)

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