Complete guide : Transfer Of Control (TOC) in HP servers

Everything you need to know about TOC i.e. Transfer Of Control reset in HP servers. Its a way to initialize system halt and memory dump in emergency.

What is TOC ?

TOC stands for Transfer Of Control! Its a way out for sysadmin when their system stops responding or hung or not taking any inputs and they need to take memory dump before resetting system. This memory dump is helpful for investigating cause of system abnormality.

Whenever TOC order (hardware signal) has been issued to system, it stops all current work and start dumping current memory information in the dump device specified in configurations. Once dumping completes, system resets.

Why to invoke TOC ?

There are many reasons like utilization being high, disk is getting full, some process going in loop, many processes forked (Error like sh: The fork function failed. Too many processes already exist.) etc etc which could bring system down to its knees. In such situation there is no way than resetting system since these issues makes system unusable or not responding. So why TOC? Even normal reset will do the job.

But if you are interested in root cause of what has happened on system which brought it down then you will need a memory dump for analysis. This memory dump can be generated when TOC is issued. Since system dont respond to user, you can not check whats happening and then memory dump is only hope for investigation after reboot. Hence, TOC reset is always recommended in case of system hung issues.

How to do TOC reset ?

1. TOC can be invoked by using TOC switch on back of your HP server.
2. Using TC command in GSP menu.
3. Using vparreset with  option (for vPars)

TOC switch :

Its located in back of your HP server normally a push button. Sometimes it also accompanied by GSP reset switch too. You need to use to activate TOC.

TC command in GSP :

Login to GSP or MP. Goto command menu using CM. Then use TC command there to reset with TOC.

    MP MAIN MENU:

         CO: Consoles
        VFP: Virtual Front Panel
         CM: Command Menu
         CL: Console Logs
         SL: Show Logs
         FW: Firmware Update
         HE: Help
          X: Exit Connection

[Server-mp] MP> cm
                Enter HE to get a list of available commands

                      (Use ^B to return to main menu.)

[Server-mp] MP:CM> TC

vparreset command :

Using -t option with vparreset command reset vPars with TOC.

# vparreset -p <vpar_name> -t