What the heck is all that DVEBMGS00 crap?

Up to now, we have discussed that a SAP instance contains three components; the DB, CI, and DI instances. But what do I SEE on the OS level when my SAP instance is up and running? The answer to this is complex, and you aren’t even close to being able to understand it all, so we will just present the big picture for now.

Besides having your database software running, and any shadow processes it might spawn, your SAP instance creates many processes when it successfully comes up. It may be configured to start at least one of every type of process SAP uses during the average day, or it may be a more specialized SAP instance that just handles user communication, leaving the more muscular work for the CI elsewhere. But every SAP instance will have at least 1 work process kicked off when it starts.

The types of work processes are as follows:

Type Description Process Instance Parameter

Dialog Process user requests in foreground dw.sap_ rdisp/wp_no_dia

Update Server uses to process mission critical updates also dw.sap_ rdisp/wp_no_vb

Update2 Server uses to process less critical updates also dw.sap_ rdisp/wp_no_vb2

Enqueue Used for lock management also dw.sap_ rdisp/wp_no_enq

Batch Process jobs in the background also dw.sap_ rdisp/wp_no_btc

Message Message server ms.sap_ N/A

Gateway Gateway server gwrd N/A

Spool Used for spool management also dw.sap_ rdisp/wp_no_spo

So, given that the German word for update starts with a V, the standard SAP instance that is the first instance on a server – i.e. System Number 00 – you get DVEBMGS00. So I can tell just by looking at the \usr\sap\\DVEBMGS00 directory on the OS level that this is a full SAP instance – it has all the parts. A SAP instance can only have 1 message server, so we know this is the main directory for the instance. When a DI is optionally installed, the name is normally in the form of D since it is subservient to the main SAP instance.

Just looking at the processes running on a server, you can pretty much tell if your SAP instance came up sucessfully or not. First, the message server comes up, and then the gateway/dispatcher starts and connects to the message server. And finally, the disp+work work threads for the dialogs, batch, and update processes start, the enqueue and spooling specific ones first. One depends on the other, the dw’s can’t start unless the gateway/dispatcher is up which can’t start unless the message server has come up successfully. The reverse is true during instance shutdown, first the dw’s go then the gateway/dispatcher, and finally the message server shutdown will always be the last thing in your log when you stop your SAP instance, it isn’t down until that messsage shows in the log.