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Kernel param.s shmseg, hp-ux, shared, S800, uxgen
Tip-No.: 2813 ( INFO2813 )

Short text

Kernel param.s shmseg, hp-ux, shared, S800, uxgen
Tip-No.: 2813

Symptom

When generating the kernel with uxgen, the value of the parameter
shmseg ( no. of Shared Memory Segments per process) has no effect.
When starting the SAP System, the trace files dev_* contain the error
message: "shmat(...) too many open files".
Cause: the max. number of Shared Memory Segments, that a process can
attach, is exceeded.

Cause

The SAP System requires a particular kernel configuration.
In particular, the no. of Shared Memory Segments ( Kernel parameter
shmseg ) must be set higher.
The kernel configuration can be checked using the command:
/ipclimits

Example:

> /bas/BIN/gen/dbg/hp/ipclimits
IPC-Limits Program V1.2 gz (92/01/10)
=============================================
Maximum Shared Memory Segment Size = 64 MB
Maximum Number of Shared Memory Segments = 120
Maximum Amount of Shared Memory Space = 64 MB (2 seg)
Maximum Semaphore Set Size = 191
Maximum Semaphore Identifiers = 56
Maximum Message Identifiers = 44
Maximum Nr of Messages in Queue = 40
Maximum Size of Messages in Queue = 8192
Maximum Byte-Amount in Queue = 16384 (4 Entries)

The entry "Maximum Number of Shared Memory Segments" must correspond to
kernel parameter shmseg.

Solution

Under certain circumstances, we noticed that the kernel parameter
shmseg in configuration file S800 had no effect.
In this case, in the generation directry ("/etc/conf/S800") in file
config.h, the value for SHMSEG (uppercase) must be set to the correct
value and the generation with "make -f Makefile" must be repeated.

Occurred previously: hp-ux 8.02 at hp-847.

Check result with "ipclimits".