-----Original Message-----
Subject: Logical system

Hello !

Does anybody know what "logical system" is ??? I have read help in =
transaction SCC4 already, but I'm confused more than before ... :-))) =
What it is good for ? What is the reason for defining it ?

Give me an explanation, please ...
Thanks !

-----Reply Message-----
Subject: RE: Logical system

Hi,

'logical system' is 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.

cheers,

-----Reply Message-----
Subject: RE: Logical system

Just a note of warning regarding choosing the Logical System name.

I know of one site where it was chosen such that it depended on the actual
system name and, therefore, had to be changed after copying production back to
acceptance. The process ran for two to three days! I have not examined how the
logical system name is used but it would appear that selection should be made
carefully to avoid the need for this if the architecture can support it.

Perhaps someone with more experience of this object could comment on its usage
and name selection.

-----Reply Message-----
Subject: RE: Logical system

yes - you should use a 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 ??).

eg., in DEV box , sys no 00, client 100, choose something like 'DEV00_100'.

cheers,

-----Reply Message-----
Subject: RE: Logical system

You state that a logical system appears to be nothing more than another label
for a client. I think (certainly cannot say I know!) that it is a little more
than that: I think it is an externally visible label for a client within a
system.

-----Reply Message-----
Subject: RE: Logical system

Thanks,

I had interpreted the term "logical" as meaning it had no relationship to a
specific instance. That's how I would use the term anyway. I take it from your
remarks and others on this thread that it is, in fact, a very instance and
client specific label - really very physical and not at all virtual/logical.

-----Reply Message-----
Subject: RE: Logical system

I know from experience that the logical system must be defined or you get
error messages all over the place during order processing stating the
logical system has not been defined.
The logical system is defined in the IMG. Don't know the transaction
identifier, but 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.
As you stated, it is assigned to the Client in Tx SCC4. (The next step in
the IMG)
I went to the IMG for help. Here is the extract at "Logical systems" level:
"Logical Systems.
The distribution of systems ( ALE ) makes it necessary to be able to
identify every system individually within a network. The "logical system" is
used to do this.
A logical system is an application system within which the applications are
coordinated to work in one database. In the SAP sense of the word, a logical
system corresponds to a client.
In the following steps, you must define every client as a logical system 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".

Hope it helps,

-----End of Message-----
 

Best regards,
SAP Basis, ABAP Programming and Other IMG Stuff
http://www.sap-img.com