INSTANCE and MULTIPLE INSTANCES

[Former Member]

Hi,

I am new to SAP, please can anyone tell me whether instances is like adding of new server and installing the sap and giving the instance numbers as (00,01,02,.....). Central Instance instance number is given as 00 and all other instances as (01,02,...).

Here, what I want the clarification is creating a new instance is adding a new server and installing SAP and instance number as 01 & coming to database, it is installed on the central instance and used by all the servers(instances) or database is separately on different server. What I understood is correct or wrong? Please help me. Thanks in advance.

[Reagan · Accepted solution]

Good Day

Please read these link:

http://help.sap.com/saphelp_nw70/helpdata/en/c4/3a5e90505211d189550000e829fbbd/content.htm

http://it.toolbox.com/blogs/sap-library/understanding-the-sap-system-instance-30172

Central Instance instance number is given as 00 and all other instances as (01,02,...).
Here, what I want the clarification is creating a new instance is adding a new server and installing SAP and instance number as 01 & coming to database, it is installed on the central instance and used by all the servers(instances) or database is separately on different server. What I understood is correct or wrong? Please help me. Thanks in advance

Not necessarily. The rule is that you cannot have same system number to multiple SAP systems on one server.

If an SAP system has CI and an AS running on one server then they need to have different system numbers.

If the CI is on one server and the AS is on another server then you can have the same system number.

You can install database and central instance on one server or in a distributed way. The application servers depend on the central instance. The application servers can be installed on the same node if the above mentioned conditions are met and also if the hardware is sufficiently sized.

Cheers

RB

[Former Member · Accepted solution]

Hi Reagan Benjamin,

                Thanks for your information. I have studied the link which you mentioned. In this link

http://it.toolbox.com/blogs/sap-library/understanding-the-sap-system-instance-30172

it is given like like this -  "In a case where you have more than one instances running on a single host, the port address numbers 3200 and 3201 are assigned in that sequence for subsequent instances."  Can you clarify this sentence. I am not getting this. More than one instance running on a single host means, SAP is installed again on the same server, but as per my knowledge we can't install the same software twice in a system.

[Reagan · Accepted solution]

Good Day

"In a case where you have more than one instances running on a single host, the port address numbers 3200 and 3201 are assigned in that sequence for subsequent instances."

32XX - The last part (XX) represents the system number.

Check this document for more info on SAP port numbers

http://scn.sap.com/docs/DOC-17124

but as per my knowledge we can't install the same software twice in a system

Why ? What is the blocking point from your point of view ?

Check the configuration I have shown below.

Example - 1

Server Name - SAPHOSTT

SAP systems :

Development System

SID - DEV

DB + CI

System number - 00

Test System

SID - TST

DB + CI + AS

CI System number - 10

AS System number - 20

Server Name - SAPHOSTP

SAP systems :

Production System

SID - PRD

DB + CI + AS

System number - 00

AS System number - 10

Example - 2

Server Names - SAPHOSTDB SAPHOSTAS

SAP system

Production System

SID - PRD

DB + CI + AS

SAPHOSTDB

DB + CI

System number - 00

SAPHOSTAS

AS

System number - 00

Cheers

RB

[Former Member · Accepted solution]

Hi RB,

Oh fine got clarity of what you are saying. Thank you for sparing your time to explain me.

[former_member192421]

Hi Sudhir,

Please see the below diagram, you will have a clear understanding.

Adding new instances means, installing Dialog Instances in new server computers in order to allocate more hardware.

Regards,

Rajkumar

[Former Member]

Hi Rajkumar,

      Thank you for your reply. Just now I am getting clear idea about the instances from all the discussions above.

[Former Member]

Dear All Sap Expert,

i have one different question.......... i will appreciate your help..

if system landscape contain (DEV, QAS, PRD)

then how we will assign  instance number to each systems include CI, DB AND APP systems

in distribute environment?

did you understand my question , if development system contain ci which i have assign 00, db assign 01, app assign 02

so what will be instance number for Quality System for CI host ?

is it 03 or again will start from 00?

please clear my doubt

thanks & regard

zahoor

[Former Member]

Hi Zaheer,

In distributed installation, for CI - 00 and if any appservers then 01,02,.......

So, DEV, QAS and PRD are separate. There is no link between instance numbers in the system landscape.

Ex:

DEV

CI -  00

QAS

CI - 00

PRD

CI - 00

Appservers 01,02,...99

But generally in any landscape there will appservers for production only.

In distributed installation, the system where DB is installed will be linked in the CI.

Regards

Sudhir Sadhu

[Former Member]

Hi Sudhir,

An SAP instance defines a group of resources such as memory, work processes and so on, usually in support of a single application server or database server within a client/server environment. Application servers share the same memory areas and are controlled by the same dispatcher process.

For an example, CI consists of Message server & enqueue server... Internally SAP will communicate within each other based on the ports like 36<instance number> for message server and so on .

Usually SAPINST will start the instance number from 00 ...

There are many  ways of installing SAPinstances.. You can also install CI & DB in a same box as well as CI & DB in different boxes.

In short, creating new instance is like adding a new server... A SAP server can have mulitple instances like Central instance, Database instance and Dialog instance...

I hope the information helps.

Thanks and Regards,

Vimal

[Former Member]

Hi sir,

Thankyou for your reply. From the above discussion what I understood is initially SAP is installed in the server, it is called as central instance(00) and DB can be installed in the CI or in any other server and can be connected to it through the IP.

If the resources are not sufficient then they will go for a new server(Instance). In the new server they will install SAP with the instance number 01. The CI communicate to other Instances through the message server which is present in the CI.

[Former Member]

Yes Sudhir,

You are correct