Re: Building high available and high performance web sites with MS

There are two technologies that you can use in conjunction with each other,
if desired, but they are TWO separate technologies, each supporting very
different goals.

Failover clustering, a.k.a. server clusters, support redundant hardware that
exposes a single virtual host name. In the case of hardware failure, the
other node picks up the services, and continues to present the same virtual
server to the network. It is a fail-safe, business resumption solution.

Federated servers, on the other hand, is the closest thing you can come to a
NLB solution for database services. A collection of servers host separate
instances of SQL Server, all with a copy of the database schema; however,
the base tables are partitioned vertically, by date, name, or some other
partitioning function, with linked servers to the other systems. Each
database contains copies of common distributed portioned views, that
aggregate the base tables from across the federation.

Now, since each server exposes this same view across the entire federation,
each is able to process data from all systems. A naive solution, would be
to introduce a load balancing algorithm to distribute client connections
equally across this federation. However, to make optimal use of such a
solution, one would need the application to code which server to connect to
based on the data and which partitioned server supported that data locally,
Data Dependent Routing.

Much of the SS2K documentation is still applicable to SS2K5, but I would
search them both as there have been some enhancements and improvements.

Failover Clustering
http://msdn2.microsoft.com/en-gb/library/ms189134.aspx

SQL Server 2000 Failover Clustering
http://www.microsoft.com/technet/prodtechnol/sql/2000/maintain/failclus.mspx

Scaling Out SQL Server with Data Dependent Routing
http://www.microsoft.com/technet/prodtechnol/sql/2005/scddrtng.mspx

Federated SQL Server 2000 Servers
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/architec/8_ar_cs_4fw3.asp

Federated Database Servers
http://msdn2.microsoft.com/en-us/library/ms190381.aspx

Best of luck.

Sincerely,


Anthony Thomas


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"Flaxen" <Flaxen@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:C29A1C86-1103-4983-BDB6-77C2740EDA1C@xxxxxxxxxxxxxxxx
What is the purpose of adding extra nodes past the 2 node cluster if
clustering is just for failover? I read about adding extra nodes when
researching and didnt see why that would be advantageous? In case
multiple
servers malfunction at the same time?

Ok, now that I know Clustering wont solve my problem, is there another
method of doing database load balancing? Would have lets say 3 servers,
each
acting as a publisher/subscriber and then a 2-node cluster acting as a
distributer work well in this situation? I feel in this solution, i would
have 3 sql servers with the same info and then a high available
distributer.

Then I assume I would need a way to make the 3 sql servers appear as one
server somehow so the code only has to reference one sql server. Maybe
round
robin dns?

Am i making this too difficult? Is there an easier solution? I cant
imagine I am the only one who needs a solution where you can scale
Microsoft
SQL servers effectively.

Thanks in advance.
"Geoff N. Hiten" wrote:

You are asking about two goals. First let me addres the availability
issue.
Microsoft clustering is a failover technology where a SQL instance can
move
between host computers in case of hardware or systems failure. The
basic
single-instance, two-node cluster (sometimes incorrectly called
Active/Passive) uses only one host at a time. You can add additional
nodes
(host computers) and instances, but the instances do not share
information
and are not "brick-type" scalable.

Right now, the way to scale SQL is to replace the host computer with a
larger one. With failover clustering, you can do this with minimal
downtime
by replacing one node at a time.

--
Geoff N. Hiten
Senior Database Administrator
Microsoft SQL Server MVP




"Flaxen" <Flaxen@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:7A300D7D-7E43-49DF-A3A7-9A134C55AA22@xxxxxxxxxxxxxxxx
Hi all. My first time posting to this newsgroup, but I think I am in
the
right place. I am in the discovery stage of building a web site that
we
anticipate will have a large amount of traffic. Our design platform
is
Windows and Microsoft SQL and the goal is to have web sites and
database
servers that are not only high available but also scalable that I can
put
in
a new server as needed to increase performance.

For the web sites, I know that I can use the NLB services of Windows
2003
standard edition. My lack of knowledge, though, is on the MS SQL
side. I
have been reading a lot of info on Microsoft SQL server failover, but
from
what I have read this tyipcally entails having two MS SQL servers
running
in
an active/passive mode.

Does Microsoft SQL Server support the ability to have multiple MS SQL
servers using the same database and appearing as one physically
database?
If
one fails, the other servers pick up the load, and if we need to add a
new
server we simply install it into the cluster?

I understand that I will need enterprise edition to accomplish the
goals
above, but are these goals even doable?

I know I can setup a bunch of SQL servers all doing transaction
replication, but that makes each server appear as its own database
server
and
I feel is not the proper solution for this.

Hope my questions make sense and looking forward to the answers.





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