SAP Note 17108 - Shared memory still present, startup fails

Symptom:

Shared memory segments remain during shutdown stopsap. Startup of the application serve fails.
Error messages appear in the dev_w... trace files:
ERROR .. ShmCreate ... shmget or shmat
ERROR .. ShmGet ...

Cause and prerequisites

Due to a program error or a crash of the application server, IPC objects (like shared memory segments and semaphores) remain and prevent a restart. The problem also appears when the application server crash takes longer than 20 seconds, e.g., because of a slow databank reaction during a rollover.

Solution
Quick fix: use program "cleanipc" to delete all the shared memories of an R/3 instance once that instance has been shut down.
Call: cleanipc remove
Example: cleanipc 00 remove ; for SAP System no. 00
Calling 'cleanipc' can be automated by adding the following
instruction in START_D....

Stop_Program_ =local cleanipc remove

Example:
#------------------------------------------------------------------
# cleanup ipc objects
#------------------------------------------------------------------
Stop_Program_01 =local sleep 10
Stop_Program_02 =local cleanipc 00 remove
CAUTION!!
'cleanipc' cannot be used while an instance is running because it
will cause the application server to crash.
Side effects:
"cleanipc" also deletes a shared memory segment "SCSA", which contains the current write pointer for the SysLog file. Therefore, during the next restart, a delay of several seconds will take place, and the system will issue the message:
"searching for overlap point in pre-existing syslog file"