Kernel parameter tuning on HP-UX, Oracle Solaris and Linux

Product documentation


Abstract

For IBM® Tivoli Storage Manager and DB2® to install and perform properly on HP-UX, Solaris, and Linux systems, you must update the kernel configuration parameters. If you do not update these parameters, the installation of DB2 and Tivoli Storage Manager might fail. If these values are not set and the installation is successful, operational issues might still be encountered when using the server.

Content

Using the db2osconf utility on HP-UX and Solaris systems

For HP-UX and Solaris systems, you can run the db2osconf utility to get recommended changes based on the size of your system. The db2osconf utility checks the current kernel configuration parameter settings, and suggests any updates that should be made. The db2osconf utility does not change the kernel parameters, but only suggests updates to help improve performance.

The suggested updates provided by the db2osconf utility are the minimum settings required to run DB2 on your system. To run both Tivoli Storage Manager and DB2, additional changes are required in addition to the suggestions made by the db2osconf utility.

The recommended values are for one Tivoli Storage Manager instance-one server for DB2 Version 9.7, Fix Pack 2 (or later).

Even though it is possible to recommend kernel parameters based on a particular DB2 database workload, this level of accuracy is not beneficial. If the kernel parameter values are too close to what are actually needed and the workload changes in the future, the DB2 database manager might encounter a problem due to a lack of interprocess communication (IPC) resources. A lack of IPC resources can lead to an unplanned outage for the DB2 database manager and a reboot would be necessary in order to increase kernel parameters. By setting the kernel parameters reasonably high, it should reduce or eliminate the need to change them in the future. The amount of memory consumed by the kernel parameter recommendations is almost trivial compared to the size of the system.

Additional details about the db2osconf utility are available at:
IBM DB2 Database for Linux, UNIX, and Windows Knowledge Center

For Solaris 10 systems, you should use PROJMOD commands to update the kernel parameters. For Solaris 9 systems, you should edit the /etc/system file to update kernel parameters.

The DBMEMPERCENT server option

For best results, deploy one instance - one Tivoli Storage Manager server on one workstation and use the default setting for DBMEMPERCENT (AUTO). With this configuration, the DBMEMPERCENT should not need to be adjusted.
For more details about using DBMEMPERCENT with Tivoli Storage Manager V6, see
http://www.ibm.com/support/docview.wss?uid=swg21444747

Modifying kernel parameters on Linux systems

To update the kernel parameters on Red Hat® and SUSE Linux®, you can run the ipcs -l command to list the parameter values and then analyze the output to determine whether any changes are required for your system.

Additional details are available at: IBM DB2 Database for Linux, UNIX, and Windows Knowledge Center

With Tivoli Storage Manager V71.1, it is no longer necessary to set the following parameters manually:
kernel.shmmni    The maximum number of segments 256 × size of RAM in GB
kernel.shmmax    The maximum size of a shared memory segment (bytes) size of RAM in bytes
kernel.shmall    The maximum allocation of shared memory pages (pages) 2 × size of RAM in bytes (setting is in 4 KB pages)
kernel.sem (SEMMNI)    The maximum number of arrays 256 × size of RAM in GB
kernel.sem (SEMMSL)    The maximum semaphores per array 250
kernel.sem (SEMMNS)    The maximum semaphores per system 256,000
kernel.sem (SEMOPM)    The maximum operations per semaphore call 32
kernel.msgmni    The maximum number of system-wide message queues 1024 × size of RAM in GB
kernel.msgmax    The maximum size of messages (bytes) 65,536
kernel.msgmnb    The default maximum size of queue (bytes) 65,536

Modifying kernel parameters on HP-UX systems
You must have root authority to modify kernel parameters.

To modify kernel parameters:
1. Enter the sam command to start the System Administration Manager (SAM) program.
2. Double-click the Kernel Configuration icon.
3. Double-click the Configurable Parameters icon.
4. Double-click the parameter that you want to change and type the new value in the Formula/Value field.
5. Click OK.
6. Repeat these steps for all of the kernel configuration parameters that you want to change.
7. When you are finished setting all of the kernel configuration parameters, select Action --> Process New Kernel from the action menu bar.

Important: The HP-UX operating system automatically restarts after you change the values for the kernel configuration parameters.

As of November 30, 2011, use the information in the following links to determine the minimum values that you should set to run Tivoli Storage Manager and DB2 together:

HP-UX recommended parameter values
http://www.ibm.com/support/knowledgecenter/SSGSG7_6.3.4/com.ibm.itsm.srv.install.doc/t_srv_krnlparms_hp.html

Oracle Solaris recommended parameter values
http://www.ibm.com/support/knowledgecenter/SSGSG7_6.3.4/com.ibm.itsm.srv.install.doc/t_srv_krnlparms_sol.html

Linux recommended parameter values
http://www.ibm.com/support/knowledgecenter/SSGSG7_6.3.4/com.ibm.itsm.srv.install.doc/t_srv_krnlparms_lnx.html


Document information


More support for:

Tivoli Storage Manager
Server

Software version:

6.1, 6.2, 6.3, 7.1.1

Operating system(s):

HP-UX, Linux, Solaris

Reference #:

7015156

Modified date:

2010-10-05

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