What is a Logical Systems in SAP?
SAP Logical System : SAP logical systems are used to identify an individual client in a system, for ALE communication between SAP systems. That’s why you see a field for ‘logical system’ in the client master data in SCC4 (table T000). You use logical systems in ALE config – this should be documented further in the IMG guide, or SALE and BALE transactions.
The naming convention for the logical system names which includes distinct IDs depending on: System ID (SID), and client number, and maybe also system number if you have more than one instance per host machine. Hostname would be useful too, but I think there’s only 10 characters in v3.1x (maybe more with long name functionality in 4.x ??).
SAP Logical System
eg., in DEV box , sys no 00, client 100, choose something like ‘DEV00_100’.
The logical systems must be defined or you get error messages all over the place during order processing stating the logical systems has not been defined. The logical systems are defined in the IMG. In 4.* it is found in the IMG > Cross Application Components > Distribution ALE > Basic settings > Logical systems > Define logical systems. Here the entry is just an identifier and a text entry.
“Logical Systems. The distribution of systems ( ALE ) makes it necessary to be able to identify every system individually within a network. The “logical systems” are used to do this. A logical systems are an application system within which the applications are coordinated to work in one database. In the SAP sense of the word, a logical systems corresponds to a client. In the following steps, you must define every client as a logical systems by first of all defining logical systems and then assigning the clients in question to the corresponding logical systems
Note: Assignments must be unique (that is, a client may only be assigned to one
logical system.
Several clients must never be assigned to the same logical system.” Reading this it does seem that it is nothing more than another identifier for a “Client”.
Also See: SAP Security and Authorisations