Active/Active configuration queries

Hi,
I completely understand that SQL-Clustering is failover
technology and not a load balancing technology.
1. What I'm wondering is when you go for Active/Active
mode, then whether both the nodes communicates with the
single instance of shared device or only 1 node
communicates with it?
2. If only 1 node communicates then what is the advantage
of Active/Active configuration over Active/Passive
configuration?
3. Also I guess Active/Active configuration requires 2
licenses of SQL-2000. Is that true?
4. I know that we can run 16 instances of SQL-2000 on a
cluster. Now, I understand that - logically, each instance
data would be different than other thats why it is a
seperate instance. So how does the client application
knows which instance data to use? How does the application
takes care of providing latest data always?
Thanks in advance
Pankaj A. Chitriv
Hi Pankaj,
I will try to answer your questions.
1. What I'm wondering is when you go for Active/Active
mode, then whether both the nodes communicates with the
single instance of shared device or only 1 node
communicates with it?
Answer - By shared device, I assume you mean shared drive. Each instance
works with it's own shared disk(s), but never will they intermix.
For example:
VirtualServer1\Instance1 has disks R:, S:, and T: in it's group.
VirtualServer2\Instance2 has disks X:, Y: and Z: in it's group.
The data in X, Y, and Z is complete separate from R, S, T and would never
ever be accessible to VirtualServer\Instance1 unless you uninstalled
Instance2.
This is true even if both instances are running on the same node (physical
machine). Instances should be thought of as COMPLETELY independent from
each other, as if they were running on completely separate machines.
2. If only 1 node communicates then what is the advantage
of Active/Active configuration over Active/Passive
configuration?
Answer - Advantage of Active/Active - You add another SQL server to your
environment. The other node isn't sitting there idly waiting for a
failover that might or might not happen. It's actually being used.
3. Also I guess Active/Active configuration requires 2
licenses of SQL-2000. Is that true?
Answer - True.
4. I know that we can run 16 instances of SQL-2000 on a
cluster. Now, I understand that - logically, each instance
data would be different than other thats why it is a
seperate instance. So how does the client application
knows which instance data to use? How does the application
takes care of providing latest data always?
Answer - You configure your client application to talk to the instance of
SQL it should be using.
For example:
1st Physical Machine Name: NodeA
2nd Physical Machine Name: NodeB
VirtualServer1\Instance1 uses Drive T: and holds accounting data
VirtualServer2\Instance2 uses Drive U: and holds marketing data
Users in the marketing department would connect to VirtualServer2\Instance2
Users in the accounting department would connect to VirtualServer1\Instance1
You would specify the SQL Instance in a UDL File, connection string, DSN,
or however your application requires you to specify the servername.
For more information and a great installation checklist, check out the
following:
SQL Server 2000 Failover Clustering
http://www.microsoft.com/technet/pro.../failclus.mspx

Active/Active configuration queries

Hi,
I completely understand that SQL-Clustering is failover technology and not a
load
balancing technology.
1. What I'm wondering is when you go for Active/Active mode, then whether
both the nodes communicates with the single instance of shared device or only
1 node
communicates with it?
2. If only 1 node communicates then what is the advantage of Active/Active
configuration over Active/Passive configuration?
3. Also I guess Active/Active configuration requires 2 licenses of SQL-2000.
Is that
true?
4. I know that we can run 16 instances of SQL-2000 on a cluster. Now, I
understand that - logically, each instance data would be different than other
thats why it is a seperate instance. So how does the client application knows
which instance data to use? How does the application takes care of providing
latest data always?
Thanks in advance
Pankaj A. Chitriv
Answers inline
Geoff N. Hiten
Microsoft SQL Server MVP
Senior Database Administrator
Careerbuilder.com
I support the Professional Association for SQL Server
www.sqlpass.org
"Pankaj" <pankajchitriv@.rediffmail.com(donotspam)> wrote in message
news:D7F79263-D4D3-4C74-9CBF-E88D95C3E7C7@.microsoft.com...
> Hi,
> I completely understand that SQL-Clustering is failover technology and not
a
> load
> balancing technology.
> 1. What I'm wondering is when you go for Active/Active mode, then whether
> both the nodes communicates with the single instance of shared device or
only
> 1 node
> communicates with it?
The cluster service arbitrates ownership. All host nodes are pysically
connected to the shared storage system, but only one node actually owns and
modifies the on-disk information
> 2. If only 1 node communicates then what is the advantage of Active/Active
> configuration over Active/Passive configuration?
>
Active-Active is really multi-instance. You load a second sql server
instance with a different set of physical shared disks.

> 3. Also I guess Active/Active configuration requires 2 licenses of
SQL-2000.
> Is that
> true?
Depends on your licensing model. Read the licensing page to be sure.
> 4. I know that we can run 16 instances of SQL-2000 on a cluster. Now, I
> understand that - logically, each instance data would be different than
other
> thats why it is a seperate instance. So how does the client application
knows
> which instance data to use? How does the application takes care of
providing
> latest data always?
Each instance has its own Network name and IP address. To the client, they
all look like different SQL servers.

> Thanks in advance
> Pankaj A. Chitriv
>
|||Thanks Geoff again (I remember you)
1. What I understand by "multi-instance" is the different Alias created
using the "Client Network Utility". Is that true? or Instance means- I'll
have to install SQL server and give different service name during
installation?
2. Although each instance has its own Network name and IP address, all of
them points to the same sql database on the shared device. Correct?
Regards,
Pankaj
"Geoff N. Hiten" wrote:

> Answers inline
> --
> Geoff N. Hiten
> Microsoft SQL Server MVP
> Senior Database Administrator
> Careerbuilder.com
> I support the Professional Association for SQL Server
> www.sqlpass.org
> "Pankaj" <pankajchitriv@.rediffmail.com(donotspam)> wrote in message
> news:D7F79263-D4D3-4C74-9CBF-E88D95C3E7C7@.microsoft.com...
> a
> only
> The cluster service arbitrates ownership. All host nodes are pysically
> connected to the shared storage system, but only one node actually owns and
> modifies the on-disk information
> Active-Active is really multi-instance. You load a second sql server
> instance with a different set of physical shared disks.
> SQL-2000.
> Depends on your licensing model. Read the licensing page to be sure.
> other
> knows
> providing
> Each instance has its own Network name and IP address. To the client, they
> all look like different SQL servers.
>
>
>
|||More Comments Inline.
BTW, this is my last answer for about a week. Vacation time.
Geoff N. Hiten
Microsoft SQL Server MVP
Senior Database Administrator
Careerbuilder.com
I support the Professional Association for SQL Server
www.sqlpass.org
"Pankaj" <pankajchitriv@.rediffmail.com(donotspam)> wrote in message
news:E0413295-17C7-4A39-A656-753AB9612811@.microsoft.com...
> Thanks Geoff again (I remember you)
> 1. What I understand by "multi-instance" is the different Alias created
> using the "Client Network Utility". Is that true? or Instance means- I'll
> have to install SQL server and give different service name during
> installation?
>
You must supply a unique Network name and IP address for each instance. You
can use the Server Network Utility to assign non-standard port addresses if
you wish.

> 2. Although each instance has its own Network name and IP address, all of
> them points to the same sql database on the shared device. Correct?
>
Wrong. No. Not that. Nada. Nope.
The physical device is "shared" in that it is physically accessable from all
host nodes. It is "shared nothing" in that only a single host actually
controls each LUN at any time. SAN storage devices present logical slices
of their storage systems (LUNS) to their connected hosts. The cluster
service arbitrates ownership so a host owns the storage resources associated
with a specific instance currently running on that host. There is NO
sharing of data storage between instances.
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> Regards,
> Pankaj
>
> "Geoff N. Hiten" wrote:
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