SAP System Architecture for Administrators

Keep this: job aid

SAP architecture cheat sheet

• System = one installation, one database, three-character SID. Instance = processes on one host, two-digit number. Client = three-digit data and user unit.
• Central services (ASCS): message server and enqueue server, once per system; ERS replicates locks for high availability.
• Application server: dispatcher, work processes, gateway (RFC), ICM (HTTP).
• Work processes: dialog (short user steps), background (jobs), update (asynchronous writes), spool (output), enqueue (where locks run in the instance).
• Look here: SM50/SM66 work processes, SM12 locks, SM13 updates, SM37 jobs, SP01 spool, SMLG logon groups.
• Routing: SAP GUI via message server and logon group; browser via web dispatcher and ICM; RFC via destinations and server groups.
• SAP S/4HANA runs only on SAP HANA; the database interface adds the client and manages buffers.
• A database-level refresh replaces every client in the target system.
• Fiori front-end server: embedded is SAP's recommendation for SAP S/4HANA; tiles depend on business roles.
• Record SID, client and front end in every piece of test evidence.