17.10 - Setting Parameters for Shared Memory - Teradata Tools and Utilities

Teradata® Tools and Utilities for IBM AIX Installation Guide

Product
Teradata Tools and Utilities
Release Number
17.10
Release Date
June 2021
Content Type
Installation
Publication ID
B035-3125-061K
Language
English (United States)
During installation, the installation process checks the values of the shared memory parameters for the required minimum values:
Parameter Maximum Value Description
semmnu 2500 Maximum number of processes that can have undo operations pending on semaphores
shmmax 4194304 Maximum size of a shared memory segment.
shmmni 200 Maximum number of shared memory segments in entire system.
shmesg 10 Maximum number of shared memory segments per process.
The Teradata Parallel Transporter Base installation does not support formula value for a kernel parameter. If the value for a kernel parameter is less than the required minimum value, the installation will recommend increasing the value to the minimum value.

If any of the above shared memory parameter is less than the minimum value, the Teradata Parallel Transporter Base installation recommends increasing the shared memory parameter to the minimum value using the kmtune command as the root user. Use the following procedure to increase the shared memory parameter to the minimum value.

  1. To check the shmseg parameter:
    /usr/sbin/kmtune -q shmseg
  2. To increase the shmseg parameter to 10:
    /usr/sbin/kmtune -s shmseg=10
  3. After the shared memory parameters are changed, rebuild the kernel using the mk_kernel command as the root user:
    /usr/sbin/mk_kernel
  4. After rebuilding the kernel, save the current vmunix file:
    cp /stand/vmunix /stand/vmunix.prev
  5. Lastly, reboot the machine:
    /usr/sbin/reboot
  6. Then, move the new vmunix file into the /stand directory:
    mv /stand/build/vmunix_test /stand/vmunix
    If there is a change to the kernel value, the following kernel parameter requires a kernel rebuild and a reboot:
    • shmmni
    If there is a change to the kernel value, the following kernel parameters do not require a kernel rebuild or a reboot:
    • shmmax
    • shmseg