Solved

Cluster vs load balancing (windows 2008 and SQL 2008)

Posted on 2008-10-08
8
2,857 Views
Last Modified: 2012-06-22
I am quite confused between the service cluster and the load balancing.  Is there any pro of Cluster over the load balancing since as I know actually load balancing can do cluster also?  E.g I have 3 machines with load balancing  A, B, C.  If  B machine is down,  the clients still switch to A or C which is the cluster purpose and provide high availability. I don't understand why need service cluster since it is active-passive only. I  think it is just used in several different resources sharing in different machines environment. or application does not  support load balancing.

Is there any called load-balanced cluster? Does it combine  service cluster and load balancing or it is a type of load-balancing only? But really don't understand the pro of combining 2 services

Another question is MS SQL 2008 supports load balancing? If so, SQL 2008 has specify setting to set the load balancing or just replication? No need to set the NLB in 2008?



0
Comment
Question by:Torus
  • 3
  • 2
8 Comments
 
LVL 60

Accepted Solution

by:
chapmandew earned 100 total points
Comment Utility
SQL Server does not support load balancing natively.  You can design your application so that it does, but it is at the design level, rather than at the sql software level.
0
 
LVL 4

Assisted Solution

by:deroyer
deroyer earned 100 total points
Comment Utility
Alright, there needs to be a little bit more understanding of the definitons to fully grasp this concept and the previous expert comment, while correct, may mislead you a little bit.  

Both clustering and load balancing are high availability solutions.  Load balancing can exist without clustering but clustering cannot exist without a virtual name *Similar to load balancing"

In windows, clustering is done at the windows server level (enterprise or above).  The cluster serice is installed on several nodes in (Active/Active Active/Passive, etc.)  The virtual IP addfress (VIP) of the cluster correlates to a load balanced DNS name that points to the active nodes of the cluster.  Chapmandew was correct that an application must be written cluster aware in order for it to function on the cluster.  Because it has to be designed to be able to recognize that this node or that node is the active resource (DB, App, etc)

Now an example of a load balanced solution would be a web server.  I will use Verizon FIOS TV for example to illustrate.  The TV service connects to a load balanced IP address that shares the load to one of over a dozen application web servers in a particular service region by pointing to each server and using the one that responds back the fastest.  If one goes down it isn't a major issue as there are many others that will pickup the load.  Now each application connects to a clustered Active/Passive SQL database server to process its workflow requests.  They connect through the Virtual IP of the cluster node which lists the active node.

As for pro's and con's as you can see there too many variables dependent upon the application and purpise... Help this helps a little bit.  


0
 
LVL 2

Author Comment

by:Torus
Comment Utility
Well. I understand that the both NLB and cluster service uses same mechanism virtual IP to connect to the server.  But really don't understand if I use IIS which supports load balancing, it is no reason to use cluster since load balancing includes failover part.  And as I said in my question, I just find that the only reason to use cluster because the software doesn't support LB or  different resources across different machines forms a cluster to provide transparent to user to access the resources

Also what is load balanced cluster?
0
Control application downtime with dependency maps

Visualize the interdependencies between application components better with Applications Manager's automated application discovery and dependency mapping feature. Resolve performance issues faster by quickly isolating problematic components.

 
LVL 4

Expert Comment

by:deroyer
Comment Utility
A load balanced cluster can either be just a fancy way of saying cluster or you can with some apps create VIPs that point to cluster VIPS and have multiple clusters.  What I mean is that technically you could create a cluster of clusters if you were so inclinded, but I have never done it.

As far as this statement goes the primary thing is to have redundancy where posible...  If you have multiple web application servers that all connect to SQL then either could be a viable option.  It really is just a matter of symantecs at that point...
"But really don't understand if I use IIS which supports load balancing, it is no reason to use cluster since load balancing includes failover part.  And as I said in my question, I just find that the only reason to use cluster because the software doesn't support LB or  different resources across different machines forms a cluster to provide transparent to user to access the resources"
0
 
LVL 2

Author Comment

by:Torus
Comment Utility
Sorry, after your explanation, I still can't got that why use cluster if an application supports load balancing or the using nature is totally different?

0
 
LVL 4

Expert Comment

by:deroyer
Comment Utility
OK Cluster fails over...  Load balancing spreads the load...
0

Featured Post

What Security Threats Are You Missing?

Enhance your security with threat intelligence from the web. Get trending threat insights on hackers, exploits, and suspicious IP addresses delivered to your inbox with our free Cyber Daily.

Join & Write a Comment

If you have heard of RFC822 date formats, they can be quite a challenge in SQL Server. RFC822 is an Internet standard format for email message headers, including all dates within those headers. The RFC822 protocols are available in detail at:   ht…
Occasionally there is a need to clean table columns, especially if you have inherited legacy data. There are obviously many ways to accomplish that, including elaborate UPDATE queries with anywhere from one to numerous REPLACE functions (even within…
This tutorial will show how to push an installation of Backup Exec to an additional server in both 2012 and 2014 versions of the software. Click on the Backup Exec button in the upper left corner. From here, select Installation and Licensing, then I…
This tutorial will walk an individual through the steps necessary to configure their installation of BackupExec 2012 to use network shared disk space. Verify that the path to the shared storage is valid and that data can be written to that location:…

763 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now