MCSG: Reasons for TOCΒΆ

Title:MCSG: Reasons for TOC
Author:Douglas O’Leary <dkoleary@olearycomputers.com>
Description:MCSG: Reasons for TOC
Date created:06/2007
Date updated:07/2008
Disclaimer:Standard: Use the information that follows at your own risk. If you screw up a system, don’t blame it on me...

Transfer of Control (TOC) is a flashy name for a hard system reboot. It’s not a system crash, so there won’t be a dump to analyze; however, it’s not a shutdown -r either, so filesystems will have to be checked and any RDBMSs will have to go through their recovery methods.

MCSG will TOC a system in order to release system resources and to ensure data integrity. There are several scenarios in which MCSG will TOC a system. They are:

  1. A two-node cluster loses heartbeat at which time a single node cluster will form. The system that loses the race to the lock disk will TOC.
  2. The cluster daemon, cmcld, dies for any reason
  3. NODE_FAIL_FAST=YES is set in a package configuration file.
  4. The cluster lvm daemon, cmlvmd, dies for any reason.
  5. System safety time is disabled via the cmsetsafety command.
  6. SERVICE_FAIL_FAST_ENABLED = YES is set (causes reboot).