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HA in Windows + SQL Server - in NW 7.0

Former Member
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Hi all,

I have to install an ABAP-only SAP ERP 2005 system using High Availability in Windows 2003 + SQL Server 2005 for my customer.

There's no way else except using MSCS so SAP can support me in case of problem?

After reading SAP installation guide (ERP 2005 SR2 ABAP on Windows SQL Server), I find 2 one-cluster options:

  • Option 1:

+ Machine 1: 1st MSCS node: ASCS, DB instance, and CI.

+ Machine 2: Additional MSCS node: ASCS, DB instance, and DI.

  • Option 2:

+ Machine 1: 1st MSCS node: ASCS, DB instance.

+ Machine 2: Additional MSCS node: ASCS, DB instance

+ Machine 3: 1 CI node.

+ Machine 4: 1 or more Dialog instance.

Unfortunately, the installation guide says that CI is a non-SPOF and my customer wants a MSCS with full clustered so the CI have to be clustered also. Customer also wants to use 3 machines only, they don't want to use 4 machines to save cost.

At first thougth, I think the infrastructure is:

  • Machine 1: 1st MSCS node: ASCS, DB instance

  • Machine 2: 1 CI node

  • Machine 3: additional MSCS node: ASCS, DB instance, and CI.

Machine 1 & machine 2 make the primary application server instance, machine 3 is for case of failover.

I don't know my infrastructure is right or not with 2 CIs. What I want is to make a full clustered solution with 3 machines.

Someone with experience please help me.

Thanks a lots,

Toan Do

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Answers (2)

Answers (2)

Former Member
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Hi Chris,

Thanks for your your info.

So your current MSCS configuration is:

+ Machine 1: 1st MSCS node: ASCS, DB instance, and CI.

+ Machine 2: Additional MSCS node: ASCS, DB instance, and DI.

+ Machine 3: DI only.

You mean CI and DI is the same in MSCS?

I used to make a distributed SAP system with 1 CI machine, 1 DB machine, and 1 DI machine. When the CI machine dies, users are unable to logon SAP anymore, DI machine becomes useless.

Back to your MSCS configuration, what I'm afraid is when machine 1 dies, does the machine 2 replace the machine 1's function? That is the DI in machine 2 become CI so SAP operations return to normal state?

former_member433984
Active Contributor
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> You mean CI and DI is the same in MSCS?

> I used to make a distributed SAP system with 1 CI machine, 1 DB machine, and 1 DI machine. When the CI machine dies, users are unable to logon SAP anymore, DI machine becomes useless.

false, if you configure logon groups it does not matter, which machine is running - message server will distribute the workload between available instances

> Back to your MSCS configuration, what I'm afraid is when machine 1 dies, does the machine 2 replace the machine 1's function? That is the DI in machine 2 become CI so SAP operations return to normal state?

see additional docu here that will answer all your questions

https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/90486554-bdc6-2a10-d39b-e143d5b2...

Former Member
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Hi Toan,

We are using the following MSCS configuration very successfully on our NW 7.0 ABAP systems:

Machine 1: Primary MSCS Node - ASCS, Central Instance (CI)

Machine 2: Secondary MSCS Node - MS SQL DB, Dialog Instance (DI)

Machine 3[n]: Dialog Instance (DI)

In this configuration the ASCS and the MS SQL DB can run on either Machine 1 or Machine 2 depending on MSCS status. The CI and DI are local to each machine and do not failover. (With Netweaver 7.0 systems the CI is not a SPOF so is really just another DI).

Hopefully this helps? Let me know if you need more info.

Thanks,

Chris