Though I could continue the phase I got stucked in a phase shortly after that:
Shadow instance couldn't be started, check 'STARTSFI.LOG' and 'DEVTRACE.LOG': RFC error system E11 nr 12 function 'UPG_IS_SHADOW_SYSTEM' failed with code 3 key SYNTAX_ERROR: Syntax error in program SAPLSDIFRUNTIME
After some deep digging I came accross an stderr-Output advising to add a route for multicast addresses:
> tail /usr/sap/E11/SUM/abap/system/E11/DVEBMGS12/work/stderr2
*** Multicast datagrams do not work properly on this host.
***
*** Description
***
*** Multicast datagrams are needed for the server internal communication.
***
*** The server terminates now!
*** Please check note 1931675 for further information
*** DISPATCHER EMERGENCY SHUTDOWN => DpSapEnvInit: DpCheckMulticast failed
SAPHOST:e11adm 118> cat stderr2
(23903) New Child Process created.
(23903) Starting local Command:
Command: dw.sapE11_DVEBMGS12_SHD
pf=/usr/sap/E11/SUM/abap/system/E11/SYS/profile/E11_DVEBMGS12_SAPHOST
*** Fatal Error
***
*** Multicast datagrams do not work properly on this host.
***
*** Description
***
*** Multicast datagrams are needed for the server internal communication.
***
*** The server terminates now!
*** Please check note 1931675 for further information
*** DISPATCHER EMERGENCY SHUTDOWN => DpSapEnvInit: DpCheckMulticast failed
And really: I isolated the system by remove default routes and add static routes to selected destinations. And I had no route for multicast.
1931675 - IP multicast configuration for dispatcher wakeup mechanism
Note says that multicast routes are required as of Kernel 7.40.
Solution:
# route add -net 224.0.0.0 netmask 255.255.255.0 eth1
After that I could make a > ./SAPup startshd
Nonetheless: the switch to 7.21 seems to have broken the installation. I was not able to get it up and running. Several compiling errors like "A Syntax error in program RSGENCOV " appeared in work log and the update stops again.
I'm resetting the update now.
Thanks all for your help!
Cheers, Tobias