Pros and Cons to Windows 2003 Clustering and Load Balancing:

You could now be asking yourself, which is better to implement, Windows clustering or load balancing hosting? To give you a quick rundown of the high-level pros and cons to each technology, consider the following. With Windows cluster hosting, you depend on the actual clustered nodes to make a decision about the state of the network and what to do in a failure. If Node A in a cluster senses a problem with Node B (Node B is down), then Node A comes online. This is done with heartbeat traffic, which is a way for Node A to know that Node B is no longer available and it must come online to take over the traffic. With load balancing, a single device (a network client) sends traffic to any available node in the load-balanced group of nodes. Load balancing uses heartbeat traffic as well but, in this case, when a node comes offline, the “load” is recalculated among the remaining nodes in the group. Also, with clustering (not load balancing), you’re normally tied down or restricted to a small number of participating nodes. For example, if you want to implement a clustered solution with Windows 2003 Advanced Server, you might use a two-node cluster. With load balancing, you can implement up to 32 nodes and, if you use a third-party utility, you can scale way beyond that number. You can even mix up the operating system (OS) platforms, if needed, to include Sun Solaris or any other system you might be running your services on. Finally, you have the option to set up tiered access to services and to mix both architectures (clustering and load balancing hosting) together. You can set up the first tier of access to your web servers as load balanced and the last tier of access as your clustered SQL databases.

With eukhost we have expertise for any feature as per your hosting requirement. We can also setup Windows Dedicated Cluster hosting along with Plesk control panel, this is something that only eUKhost can provide.

This would only happen if the Cluster services has been installed before installing and configuring MSDTC Service. Hence it is highly recommended that you first install and configure MSDTC and then configure the Windows Cluster Service.

Event ID: 4097
Description:
MS DTC started with the following settings: Security Configuration (OFF = 0 and ON = 1): Network Administration of Transactions = 1, Network Clients = 0, Distributed Transactions using Native MSDTC Protocol = 1, Transaction Internet Protocol (TIP) = 0, XA Transactions = 1.

OR

Event ID: 4395
Description:
MSDTC detected that MSDTC related information in the local registry is different from that in the shared cluster registry. Error Specifics: d:ntcomcom1xdtcsharedmtxclumtxclusetuphelper.cpp:541, CmdLine: C:WINNTSystem32msdtc.exe, Pid: 796
Data:
0000: 05 40 00 80 .@.?

OR

Event ID: 4384
Description:
MS DTC was unable to start because the installation was not configured to run on a cluster. Please run comclust.exe and restart MS DTC. Error Specifics: d:ntcomcom1xdtcsharedmtxclumtxclusetuphelper.cpp:668, CmdLine: C:WINNTSystem32msdtc.exe, Pid: 796

OR

Event ID : 7024
Source : Service Control Manager
Description: The MSDTC service terminated with service specific error 3221229584.

Initially you should try and run the command below and check if it solves the problem:

msdtc -resetlog

If that does not help then follow the fix below:

1. Delete the DTC resource
2. Delete MSDTC folder from the quorum disk.

On Node 1:

– Stop the Cluster Service

– Remove Enable network DTC  Service with the command below:

msdtc -uninstall

Make sure to check the Success in the Event logs.

– Verify that the following registry key has been removed as well.. if not then remove it manually.

HKEY_CLASSES_ROOTCID
HKEY_LOCAL_MACHINESOFTWAREMicrosoftMSDTC
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesMSDTC

– Reboot the Server

– After the Server is back online reinstall Enable network DTC Service with the command below:

msdtc -install

Now create the DTC resource on Node 1 and it should come online.

Now on Node 2

– Stop the Cluster Services.

– Evict Node 2 from the Cluster

– Remove Enable network DTC  Service with the command below:

msdtc -uninstall

Make sure to check the Success in the Event logs.

– Verify that the registry key has been removed as well.. if not then remove it manually.

– Reboot

– Reinstall Enable network DTC Service with the command below:

msdtc -install

– Verify that the Service has now Started and also registry keys created.

– Rejoin the node back into the cluster.

After installing a SQL Server failover cluster, the node hosting the SQL Server resource uses the Service Control Manager to check every 5 seconds whether the SQL Server service appears to be running. This “LooksAlive” check does not impact the performance of the system, but also does not do a thorough check; the check will succeed if the service appears to be running even though it might not be operational. Because the LooksAlive check does not do a thorough check, a deeper check must be done periodically; this “IsAlive” check runs every 60 seconds.

The IsAlive check runs a SELECT @@SERVERNAME Transact-SQL query against SQL Server to determine whether the server can respond to requests. Although a reply to the IsAlive query confirms that the SQL Server service is available for requests, it does not guarantee that all user databases are available, or that the user databases are operating within necessary performance/response-time requirements.

If the IsAlive query fails, the IsAlive health check is retried five times and then it attempts to reconnect to the instance of SQL Server. If all five retries fail, the SQL Server resource fails. Depending on the failover threshold configuration of the SQL Server resource, the failover cluster will attempt to either restart the resource on the same node or it will fail over to another available node. The IsAlive query tolerates a few errors, but ultimately it fails if its threshold is exceeded.

During failover of the SQL Server instance, SQL Server resources start up on the new node. Windows clustering starts the SQL Server service for that instance on the new node and SQL Server goes through the recovery process to start the databases. After the service is started and the master database is online, the SQL Server resource is considered to be up. Now the user databases will go through the normal recovery process, which means that any completed transactions in the transaction log are rolled forward (the Redo phase), and any incomplete transactions are rolled back (the Undo phase). In SQL Server 2005 Enterprise Edition, each user database will be available to the user once the Redo phase completes; for the other editions, as with all previous versions, each user database is unavailable until the Undo phase completes. The length of the recovery process depends on how much activity must be rolled forward or rolled back upon startup. The ‘recovery interval’ sp_configure option of the server can be set to a low number to avoid longer Redo recovery times and to speed up the failover process. The Undo recovery time can be reduced by using shorter transactions so that any uncommitted transactions do not have much to roll back.

MS SQL 2005 Server was released after 5 servers of it previous SQL version, MS SQL 2000, Hence it required allot to revisions to cope up with the current windows development environment. Therefore MS SQL 2005 SP2 had major changes in it, with too many performances and security fixes. Microsoft could not add few revisions due to its basic development structure however they had all the scope to introduce them in SQL 2008 release. And indeed, MS SQL 2008 has many installation as well as performance fixes being applied to it and allowing Windows Administrators to have full control on SQL activities. The biggest advantage of SQL 2008 over SQL 2005 is the ability to manage and maintain server performance. SQL 2008 does not require too much resource which is the best deal for today’s Shared Hosting environment. Also an upper hand to whose to do not want to invest too much on hardware of their dedicated servers just to run SQL server on it.

I have tried to gather the major improvement introduced by Microsoft on SQL 2008 from Internet which is an advantage over SQL 2005 however it all depends on what features are useful to you in the development of your ASP .NET applications. But switching to Microsoft SQL 2008 is definitely going to improve the performance even if you don’t use any of the below feature. And not to forget that with the release of SQL 2008, Microsoft will announce “End Of Life” for SQL 2000 version, which will mean that there won’t be any official support or update release for SQL 2000.

Major difference between SQL 2005 and SQL 2008.

* Easy Upgrades: Version upgrades are now very easy and effective with SQL 2008.
* Resource Restriction Governor: We set a restriction on a users or groups from consuming high resources. This is a very good feature that can be used on Windows shared server with SQL database to maintain the performance.
* Dates and Times settings: New data types such as: Date, Time, Date Time Offset has been introduced.
* Improved Full Text Search: Ability to backup Native Indexes and also thesaurus them as metadata.
* External Key Management: This unique can store Keys separately and not with the data.
* Improved SQL Server Analysis Service: It now has improved Stacks and computes block faster.
* Improved Installation: Microsoft has added an option where you can uninstall Disk images and service packs.
* Data Synchronizing: A Development of databases used in applications that frequently get disconnected.
* Transparent Data Encrypts: It has the ability to encrypt full SQL database with different encryption Methods.

* SQL Server Integration Service: SQL 2008 Server has improved multiprocessor support and faster lookups in compare to SQL 2005.
* Change Data Capture: Allows all changes to be captured and queried. (Enterprise). Also allows us to get detailed information on what changes has happened to which rows after a specific version.
* LINQ: A Development query language for accessing multiple type of data like XML and SQL at the same time.
* Hot Plug CPU: With this feature to an add CPUs on fly for your SQL server to use.
* Microsoft Office 2007 integration: One can use MS OFFICE as an SSRS template, like SSRS to WORD.
* Spatial Data types: Data types for storing Longitude, Latitude and GPS entry of a particular database.
* MERGE: A new TSQL command as a combination Update, Insert and Delete.
* Encrypted Backups: We can execute it at the time running backups to prevent tampering from external resource.
* Data Compression: This feature is different as it allows us to manage data compression at table level to enhance performance.
* Dynamic Development: Latest Visual Studio and ADO options along with ASP .Net 3.
* Reporting Server Performance: Unlike in SQL 2005 we can set threshold on Reporting server for memory management.
* Performance Studio: It is a Gallery that has collection of monitoring tools enhanced performance.
* Audits: A very power feature for monitoring the data access of your SQL database.
* Table Value Parameters: SQL 2008 database has ability to insert entire table into a stored procedure.
* Entity Database Services: (LOB) Line Of Business framework and (eSQL) Entity Query Language.

No doubt that Microsoft has improved all the features that has been used by hosting services. Even SQL Cluster in version 2008 has few major advantages since every one in today world wants to have their site up all the time with 100% uptime. I hope I get some time to write on “MS SQL 2008 Clustering..“