NLB Web App accessing Cluster SQL 2005

Hello Friends
I have a project that will use Failover Cluster for SQL 2005 and NLB for the
web server front-end (using IIS).
That web application will be developed in-house. there are any special
programming considerations that the programmers must embed in the application
in order to support the special features of Failover and NLB clusters?
Does the web App Server must be Cluster-Aware to interact to SQL 2005
Failover Cluster?
Can you please give me any links to some documents that reflect these
situations?
Thanks for Help
Bruno
No. If it can connect to the SQL Server, you are set for the application.
Mike
http://www.solidqualitylearning.com
Disclaimer: This communication is an original work and represents my sole
views on the subject. It does not represent the views of any other person
or entity either by inference or direct reference.
"Bruno" <Bruno@.discussions.microsoft.com> wrote in message
news:D6B04BF1-9730-46AA-A6E9-EBFC5C6B4C2D@.microsoft.com...
> Hello Friends
> I have a project that will use Failover Cluster for SQL 2005 and NLB for
> the
> web server front-end (using IIS).
> That web application will be developed in-house. there are any special
> programming considerations that the programmers must embed in the
> application
> in order to support the special features of Failover and NLB clusters?
> Does the web App Server must be Cluster-Aware to interact to SQL 2005
> Failover Cluster?
> Can you please give me any links to some documents that reflect these
> situations?
> Thanks for Help
> Bruno
|||Any SQL client application can connect to a SQL Cluster with no changes. I
recommend using non-persistent connections so the web app can recover in
case of a cluster failover, but that has been general programming practice
for a while now. Your NLB session model and the application session model
will need to work together. I.E. if you only support local sessions in IIS,
you will need to make sure your NLB sessions are "sticky". Your Network
Engineer can help with this.
Geoff N. Hiten
Senior Database Administrator
Microsoft SQL Server MVP
"Bruno" <Bruno@.discussions.microsoft.com> wrote in message
news:D6B04BF1-9730-46AA-A6E9-EBFC5C6B4C2D@.microsoft.com...
> Hello Friends
> I have a project that will use Failover Cluster for SQL 2005 and NLB for
> the
> web server front-end (using IIS).
> That web application will be developed in-house. there are any special
> programming considerations that the programmers must embed in the
> application
> in order to support the special features of Failover and NLB clusters?
> Does the web App Server must be Cluster-Aware to interact to SQL 2005
> Failover Cluster?
> Can you please give me any links to some documents that reflect these
> situations?
> Thanks for Help
> Bruno
|||You need to have reconnect logic built into the application. Whenever a
failover occurs, you will loose connectivity. The advantage of this
solution, however, is that the failover happens automatically, and is
relatively brief.
On the NLB, you need to program "stateless" apps. That is, you can not
guarantee that recovered session are redirect to the same web server during
each pass. If only one server is aware of the state, you find the user
orphaned if redirected to one of the other servers.
Also, to keep your solution clean and to harden security, consider using
some sort of middleware, either through dedicated application hosts, or some
sort of messaging platform.
Sincerely,
Anthony Thomas

"Bruno" <Bruno@.discussions.microsoft.com> wrote in message
news:D6B04BF1-9730-46AA-A6E9-EBFC5C6B4C2D@.microsoft.com...
> Hello Friends
> I have a project that will use Failover Cluster for SQL 2005 and NLB for
the
> web server front-end (using IIS).
> That web application will be developed in-house. there are any special
> programming considerations that the programmers must embed in the
application
> in order to support the special features of Failover and NLB clusters?
> Does the web App Server must be Cluster-Aware to interact to SQL 2005
> Failover Cluster?
> Can you please give me any links to some documents that reflect these
> situations?
> Thanks for Help
> Bruno