maximum number of shared-memory identifiers exceeded. (1137)

Bom dia,

Estou migrando de servidor de banco de dados. Estou passando de uma máquina de 16GB para uma de 24GB de memória, mas quando estou startando o banco esta dando o seguinte erro, "maximum number of shared-memory identifiers exceeded. (1137)".

Estou usando Linux RedHat 4.8.

Baixando os parametros do Banco (-B) o banco sobe, mas perco perfomance daí.

Estive vendo que precisaria alterar os parametros de Kernel do Linux, o parametro SHMMNI, mas que valor deveria colocar? Como calculo o valor desse parametro? É algum calculo em relação a quantidade de memória?

Obrigado desde já.

Material retirado do Prokb - Documentação Progress

Status: Verified

GOAL:

Tuning the UNIX Kernel tips and recommendations for Progress
Applications.

GOAL:

What are the Progress related kernel parameters?

GOAL:

Suggestions for tuning the UNIX Kernel parameters for Progress

GOAL:

Tips on tuning the UNIX Kernel for Applications

FACT(s) (Environment):

Progress 9.x
OpenEdge 10.x
UNIX

FIX:

This solution outlines the UNIX kernel parameters that might require
tuning as a result of installing a Progress application.

In many cases the default values for most of the UNIX kernel are
sufficient. In other cases, the Progress application runs for some
time without requiring any kernel tuning but as more users are added
to the UNIX system and/or the number of processes executed increases,
Progress might return system errors that indicate a shortage of some
resource (memory, number of files that can be opened by a user ...).

When this happens it might be necessary to re-tune the kernel
parameters and generate a new kernel.

Where applicable, this solution indicates whether a particular
parameter is no longer required, where the value for the parameter is
now dynamically allocated in some UNIX or Linux Systems, or where
parameter in a Version of UNIX is superseded by another UNIX Version
kernel parameter.

NOTE: Kernel parameter names vary from system to system. This solution
provides an overview so that you can direct the user/customer to the
correct kernel parameter on the particular system. If you are in
doubt, consult your UNIX system documentation.

This Solution is only for informative purposes.

What is the kernel?

The kernel is the heart of the UNIX operating system. It manages
memory, schedules processes, manages I/O, and does all other
lower-level tasks that make the system work. The kernel is not a
process (like the programs that you run from a terminal). It
pre-exists all processes and is responsible for starting the first
process.

Because it is so important, the kernel has some key privileges. It is
always resident in the processor's physical memory. Other programs can
be swapped or paged to disk, but not the kernel.

Current kernel parameter values can be seen as follows:

The name of the kernel configuration file and its location varies from
system to system.

On System V machines, look for the configuration files in
/etc/conf/cf.d. The tunable parameters are usually located in the
mtune file. Normally there is a second file in the kernel
configuration directory that is used to modify the parameters (Never
modify the master file mtune).
This second file (sometimes called stune) is used to modify a
parameter to any value between the minimum and maximum values defined
in the master file (mtune).

NOTE: If you are in doubt, consult your system documentation.

On some System V systems, you can log in as root and type "sysdef" at
the command line to see the current values. If this is not possible,
you could enter the system administration shell (a menu-driven
interface SMIT on AIX, sysadmsh on SCO) and view the kernel settings.

Some example directory locations for the files are:

/etc/conf/cf.d
/usr/kvm/sys/sun4/conf
/stand/system

The most common important kernel parameters are as follows.

General Kernel Parameters:

NPROC:
The maximum number of simultaneous processes that the system can run.

MAXPROC, MAXUP:
The maximum number of processes that any user (any user ID number) can
have at one time.

NFILE:
The maximum number of files (system-wide) that can be open at any
time.

NOFILES or NFILE:
The maximum number of open files the process might have. When this
limit is exceeded, attempts to open files fails and errno is set to
EMFILE.

ULIMIT:
The size of the largest file that a process can create. There are
user-level ways of overriding this kernel limit, such as the ulimit
command and the ULIMIT line in /etc/default/login.

Memory Management Parameters:

MAXUMEM:
The maximum amount of memory that is used to run a process.

MAXPMEM:
Specifies the amount of physical memory in use ages. The value 0 means
"use all of. physical memory".

SVMMLIM and HVMMLIM:
NOTE: In the following parameters, the "S" prefix indicates soft
limits, and "H" the hard limits. Any user process can change its soft
limits up to the corresponding hard limit. Only root can increase the
hard limits.

SVMMLIM:
The soft limit that specifies the maximum address space that can be
mapped to a process. Attempts to increase a process's address space
beyond this value fails with an ENOMEM error.

HVMMLIM:
The maximum value of SVMMLIM.

Streams Parameters:

Progress only requires STREAMS to be installed. It does not require
specific values for the streams parameters. When you see the system
Error:

793 - Select Ret -1, errno 11 you must install streams.

Inter-Process Communication (IPC) Parameters:

SHMMNI:
The maximum number of shared memory identifiers allowed for the
system.

SHMALL:
The maximum number of in-use shared memory segments allowed for the
system. Some systems do not have this parameter. Some Systems increase
this value dynamically.

SHMMAX:
The maximum size of a single shared memory segment. Some systems call
this parameter SHMSIZE.


SHMSEG:
The maximum number of shared memory segments a single process can
attach to. Some systems do not have this parameter. Some Systems
increase this value dynamically.

SEMMNI:
The maximum number of semaphore identifiers that are allowed for the
system.

SEMMSL:
The maximum number of semaphores allowed per semaphore identifier
(semaphore set).

SEMMNS:
The total number of semaphores allowed for the system.

SEMMNU:
The maximum number of semaphore undo structures allowed for the
system.

Progress and General Kernel Parameters:

As more processes are executed simultaneously on a machine, it might
be necessary to increase the NPROC parameter. If you exceed the NPROC
or NSWAP parameter, Progress returns the error message:

Too many subprocesses, cannot fork. Errno=<number>. (358)

Unable to fork process.

Progress statements OUTPUT THROUGH and INPUT THROUGH open pipes to
UNIX that create additional processes on the system. If the problem is
related to NSWAP, you could try reducing the local buffer (-l) or edit
buffer (-e) start up parameters.

In some cases, one particular user could require additional processes
to be executed and might require the MAXPROC, MAXUP parameter to be
increased.
If additional files are opened as a result of increasing the number of
processes that are executed or as a result of converting a database
from single volume to multi volume, you might need to increase the
NFILE, NFILES parameters.

Progress and UNIX shared memory:

Progress uses shared memory to allow multiple server processes and
self-service client processes concurrent access to a database, and to
coordinate their activities.

The shared memory area contains the buffer pool, lock table, log
buffers, and other shared data structures. When the database is
started (via the PROSERVE command), the broker creates and initializes
the shared memory area of the required size. The size is based on the
values of various startup parameters that determine the sizes of the
data structures.

In UNIX systems, shared memory consists of one or more segments. Each
segment is identified by a system-wide unique number that is assigned
by the process that creates the segment. Progress derives the
identifier from the inode of the .db file.

There are several UNIX kernel parameters that limit the number and
size of shared memory segments. In addition, Progress has an internal
limit on the size of a single shared memory segment. If the shared
memory size computed by the broker is larger than the maximum segment
size allowed, the broker creates multiple s.egments to reach the
required total.

The total amount of shared memory that can be allocated is:

SHMMAX * SHMALL (or SHMMAX * SHMMNI).

When you install Progress, you might have to increase the values of
these parameters. Note that if you are running other software that
also uses shared memory, you must take into account the combined
requirements.

Recommended settings:

NOTE: The following recommended settings are for Progress
applications. The values required by Progress must be added to the
current kernel parameter values. In other words, the following
recommendations do not take into account the requirements of the UNIX
operating system and/or any other application that uses shared memory
and semaphores. Consult your system documentation to determine UNIX's
requirement.

SHMMNI:
Depends on the number of active databases, the values of startup
parameters, and the value of SHMMAX. The larger SHMMAX is, the fewer
segments Progress creates. 64 is probably a good value to start with.
If you set this value too low, you might get Progress Error 1137 or
1138.

SHMALL:
The same as SHMMNI. If you set this value too low, you might get
Progress Error 1137 or 1138.

SHMSEG:
The setting depends on the number of active databases, the values of
startup parameters, and the value of SHMMAX. The larger SHMMAX is, the
fewer segments Progress creates. When self-service clients connect to
multiple databases, the shared memory segments for the database are
attached. 16 is probably a good value to start with. If you set this
value too low, you may get Progress Error 1175, 1719, or 1720.

SHMMAX:
This parameter limits the size of a single segment. Progress creates
one smaller segment if less shared memory is needed.

If you set this value too low, Progress creates many small segments,
possibly overflowing the limits SHMMNI, SHMSEG, or SHMALL.

The units that you use to specify a value for SHMMAX vary from system
to system. Some units use bytes, others use "clicks" (page size).
Consult your system manuals for the proper units.

NOTE: The amount of kernel memory required for shared memory
descriptions (not the shared memory itself) is relatively small, so
setting SHMSEG, SHMMNI, SHMALL higher than your current needs probably
won't affect performance.

Shared memory is not used for single-user sessions. Clients that
connect to a remote database on a server machine do not use shared
memory on the client machine.

NOTE: The Blocks in Database Buffers (-B), Lock-table Entries (-L),
and Number of Users (-n) startup parameters all affect shared-memory
usage. The Number of Users (-n) and Maximum Servers (-Mn) parameters
affect semaphore usage (each user or server process uses one
semaphore). Before reconfiguring your kernel to increase shared memory
or semaphore allocation, see whether you can lower these startup
values.

Progress and UNIX Semaphores:

Progress uses UNIX Semaphores to synchronize the activities of server
processes and self-service client processes that are connected to a
database. The semaphores are created and initialized by the broker
when the database is started.

UNIX semaphores are grouped into semaphore sets. Each semaphore set
has a unique identifying number called a semid. Within a semaphore
set, individual semaphores are identified by an integer that ranges
from 0 to one less than the size of the semaphore set.

The Progress broker creates a semaphore set when the database is
started. The size of the set is the number of users (-n parameter)
plus the number of servers (-Mn parameter) plus 4.

Recommended settings:

SEMMNI:
One per active database. If you set this value too low, you might get
Progress Error 1131.

SEMMSL:
Maximum number of users on any database plus (+) the maximum number
of s.ervers for any database plus (+) 4 plus (+) the number of
Asynchronous Page Writers (APW) plus (+) Before Image Writer (BIW)
plus (+) After Image Writer (AIW) plus (+) Watchdog Process.
If you set this value too low, you might get Progress Error 1093 or
1130.

SEMMNS:
SEMMSL multiply by (*) the number of active databases. If you set
this value too low, you might get Progress Error 1093, 1131 or 1195.

SEMMNU:
Set equal to one per Progress process connecting to a database. (each
server process, self-service client, page writer [6.3], BI writer
[6.3], AI writer [6.3], watchdog[6.3], PROSHUT. PROMON.
If you set this value too low, you might get Progress Error 1081.

To avoid system errors set SEMMNU = SEMMNS.

NOTE: The amount of kernel memory required for semaphores is
relatively small, so setting the limits higher than your current needs
probably won't affect performance.

Semaphores are not used for single user sessions. Clients that connect
to a remote database on a server machine do not use semaphores on the
client machine.

MAXUMEM: Maximum address space for a single user.
.