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DB2 on Linux

Tuning for Write-Heavy Loads

The Linux Page Cache and pdflush

Tuning for Write-Heavy Loads

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DB2 scripting

Yet Another Article on Advanced Scripting

Modifying kernel parameters (Linux)

Modifying kernel parameters (Linux)

Before installing DB2 UDB, you may want to update your Linux kernel
parameters. DB2 UDB automatically raises the IPC limits where necessary. You
might still want to raise these limits further depending on your particular
needs.

Prerequisites

You must have root authority to modify kernel parameters.

Procedure

To update kernel parameters:

RedHat and SuSE
Systems using a 2.4.x series kernel have a default value for the message
queue parameter (msgmni), which allows only a few simultaneous connections to
DB2. Semaphore array parameters also have to be changed for DB2 to run
successfully. To check shared memory segment, semaphore array, and message queue
limits, issue the ipcs -l command.

The following is the output from the ipcs -l command.

   # ipcs -l

------ Shared Memory Limits --------
max number of segments = 4096 // SHMMNI
max seg size (kbytes) = 32768
max total shared memory (kbytes) = 8388608
min seg size (bytes) = 1

------ Semaphore Limits --------
max number of arrays = 1024 // SEMMNI
max semaphores per array = 250
2 max semaphores system wide = 256000
max ops per semop call = 32
semaphore max value = 32767

------ Messages: Limits --------
max queues system wide = 1024 // MSGMNI
max size of message (bytes) = 65536
default max size of queue (bytes) = 16384 // MSGMAX

Modify the kernel parameters by adding the following entries to the default
system control configuration file, /etc/sysctl.conf:

2      kernel.msgmni = 1024
2 kernel.sem = 250 256000 32 1024

where

   max semaphores system wide = 
max number of arrays x max semaphores/array

Run sysctl with -p parameter to load in sysctl settings
from the default file /etc/sysctl.conf.

   sysctl -p 

The entries from the sysctl.conf file are read
during startup by the network initialization script.

On some distributions you may be required to add sysctl -p
in one of the system initialization files (for example, rc.local) so
that kernel parameters are set after each reboot.

Installing DB2 Version 8.1 for Linux

Speed-start your Linux app: Installing DB2 Version 8.1 for Linux

DB2 ICE — Scaling Data with Linux Clusters

DB2 ICE — Scaling Data with Linux Clusters

DB2 ICE — Scaling Data with Linux Clusters

Up and Running with DB2 for Linux

IBM Redbooks | Up and Running with DB2 for Linux

Leverage data partitioning for scalability and high performance on Linux

Leverage data partitioning for scalability and high performance on Linux

Leverage data partitioning for scalability and high performance on Linux

DB2 memory and file cache performance tuning on Linux

DB2 memory and file cache performance tuning on Linux

DB2 memory and file cache performance tuning on Linux

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