Central instance and SAP instance

[former_member199632]

hello,

Im confusing with Central Instance (CI) and SAP instance (Application Instance)

According to my understanding, i think SAP instance is running on all the Aplication servers. (if having 4 Application servers, in all those servers, SAP instance is running concurrently)

But Central instance is running on 1 of the Application servers only.

- How will the SAP decides on which Application should run the central instance.

Will that CI change automatically time to time.... or do we need to allocate 1 Application server as CI server, when doing the installation.

Is there any relationship between Message server and Central instance.

Does CI contains message services and enqueue service...

plz help me to reslove these issues

Rgds,

Edited by: zerandib on Apr 25, 2010 10:45 AM

[Former Member]

Hi,

When You install SAP system first it will install the Central instance(will have all the work processes) .

Centreal instance will have the message server. (It will do the load balancing)

Enque services are loking and uloking the database objects for consistancy this will also will be available tin CI only.

after that wat ever u install comes under application servers only. (this wont have message server will have only dialog wp) according to u r requiremnt u can configure this applicaiton server work processes(suppose if u want to use this only for backgroup jobs u can chage the work process to BGD min 2 work process are req for for any applicaiton servers).

Applicaion server can be use for load balancing . to reduce the load on the central instance. using SMLG trasaction.

thanks