Cluster question

Cluster question

Post by Geoff N. H » Sat, 15 May 2004 09:26:17


Yes it is possible, but you would have to have enough resources to run all
the applications. BTW, I think you don't quite understand the
term-active-active. That refers to a specific SQL 7.0 technology that
allowed each nost node to run a separate instance. SQL 2000 either has
single-instance or multi-instance clustering with the host nodes as complete
peers.

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

I support the Professional Association for SQL Server
www.sqlpass.org



databases the other will be purely an application server which amongst other
things will access the database. If we cluster the two servers and setup sql
server active/passive clustering can we continue to use 2nd node as
application server but as failover for sql server?
 
 
 

Cluster question

Post by YnVydF9raW » Wed, 01 Nov 2006 23:20:01

My employer is asking to do an Active / Active SQL 2000 cluster to utilize
both servers. Problem is, I don't think SQL 2000 supports an Active/Active
solution because both would need access to the disk which isn't possible...
The only time an Active / Active cluster can work is when you have multiple
instances which allows Node A to use the disk for one instance and Node B to
utilize the disk for a different named instance.

Can someone clarify for me? Thanks.
--

 
 
 

Cluster question

Post by Tom Morea » Wed, 01 Nov 2006 23:23:51

Each instance of SQL Server will require its own disk resources. Thus, if
SQL1 owns E: then SQL2 cannot have an E: drive. SQL 2000 supports up to 16
instances within the same cluster. We don't use the term Active/Active any
more.

--
Tom

----------------------------------------------------
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA, MCITP, MCTS
SQL Server MVP
Toronto, ON Canada
.


My employer is asking to do an Active / Active SQL 2000 cluster to utilize
both servers. Problem is, I don't think SQL 2000 supports an Active/Active
solution because both would need access to the disk which isn't possible...
The only time an Active / Active cluster can work is when you have multiple
instances which allows Node A to use the disk for one instance and Node B to
utilize the disk for a different named instance.

Can someone clarify for me? Thanks.
--
 
 
 

Cluster question

Post by Edwin vMie » Wed, 01 Nov 2006 23:27:28

"when you have multiple instances which allows Node A to use the disk for
one instance and Node B to utilize the disk for a different named instance."
--> correct

what you might want to look into is :
scalable shared databases, where multiple SQL 2005 (enterprise)
servers are accessing a read-only volume.
there are many restrictions to this

Please see ; http://www.yqcomputer.com/ ;en-us;910378
for more info on this




Active/Active
possible...
multiple
to
 
 
 

Cluster question

Post by Arnie Rowl » Thu, 02 Nov 2006 00:50:37

Each instance requires it own dedicated disk resources that cannot be
shared, and databases CANNOT be shared between instances. Those dedicated
resources cannot have the same drive assignment.

Instance A has SAN drive G, H,
Instance B has SAN drives M, N

Upon failover of Instance A, Physical computer B now runs both Instance B
AND Instance A, and Drives G, H, M, N.

This has been a very simplistic example, but hopefully you now understand a
bit better.

--
Arnie Rowland, Ph.D.
Westwood Consulting, Inc

Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous

You can't help someone get up a hill without getting a little closer to the
top yourself.
- H. Norman Schwarzkopf
 
 
 

Cluster question

Post by YnVydF9raW » Thu, 02 Nov 2006 03:55:01

Roland, very clear, thank you.

Now, slightly off but still for clustering, how do I administer the
traditional sp_configure settings? I'm speaking of memory for myself but
that raised the larger question, How do I administer the server? I'd assume
through the virtual server name since on the back end the Master and MSDB are
really being written to by the Active node... Am I correct? If I want to
give the server more or less memory, can I do so through the Enterprise
manager interface?
 
 
 

Cluster question

Post by Arnie Rowl » Thu, 02 Nov 2006 04:23:40

ach server in the cluster is still an independent server; configuration is
done the same way as a stand alone server. However, you need to configure
with the understanding that both instances MAY have to operate on the same
box.

So if the box has 8 GB of memory, then you don't assign all 8 GBs to the
default instance on that box. If you did, when there is a failover, there
will be no memory for the 'visiting' instance.

If InstanceA has a minimum memory of 4 GB, and Instance B also has a minimum
memory allocation of 4 GB, and the server only has 8 GB, then upon failover,
the 'visiting' instance will be memory starved and will most like not come
online. (You have to make sure that there is enough memory for the OS as
well.)

Let's say both boxes have 8 GB. InstanceA contains large, heavily used
databases, so it is allocated 5 GB as a maximum, and InstanceB is less
demanding, so it is allocated 2 GB as a maximum. Upon failover, the two
instances require 7 GB, and leave 1 GB for the OS and memory management.

'Bean counters' will complain since it appears that InstanceB only needs 3
GB for the server, and adding an addition 5 GB is seen as a waste. However,
you have to consider the cost of the 'unused' 5 GB on InstanceB as insurance
payments for future availability. (And the same for the 'unused' 2 GB on
InstanceA.)

Thing to remember with configuration, is that upon failover, all instances
must be able to work (albeit perhaps not performing quite as well) on one
box. Most Server wide configuration settings 'should' be the same. Memory is
the most common setting that is different between Instances.

--
Arnie Rowland, Ph.D.
Westwood Consulting, Inc

Most good judgment comes from experience.
Most experience comes from bad judgment.
- Anonymous

You can't help someone get up a hill without getting a little closer to the
top yourself.
- H. Norman Schwarzkopf


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