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.

[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