Cluster question -- sql server clustering

burt_king
10/31/2006 10:55:01 AM

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?

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Arnie Rowland
10/31/2006 11:23:40 AM

Each 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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Edwin vMierlo
10/31/2006 2:27:28 PM

"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://support.microsoft.com/default.aspx?scid=kb;en-us;910378
for more info on this

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