Communicator e3000 MPE/iX Release 7.5 (Software Release C75.00): HP e3000 MPE/iX Computer Systems > Chapter 5 Technical Articles

UPS Monitor/iX and UPSUTIL Enhancements

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By Bob Berliner - Commercial Systems Division

Introduction

In response to user community requests, the UPS Monitor/iX subsystem of MPE/iX has been enhanced in Release 7.5 to provide new capabilities related to the system's handling of AC power failures at UPS devices.

The UPSUTIL utility program for UPS subsystem management has been correspondingly enhanced to support the new features of UPS Monitor/iX.

UPS Monitor Enhancements

New UPS subsystem configuration options have been added to the UPS Monitor's configuration file facility. The new options permit users (System Managers) to specify and make use of a custom-tailored MPE/iX Command File to control the HP e3000 system's behavior in the event of a UPS-device-detected AC power failure lasting longer than a user-specified amount of time.

The primary benefit of this "powerfail command file" enhancement is that it can be used in conjunction with another Release 7.5 enhancement, the new CI-based ":shutdown" command, to cause an orderly system shutdown when the system is notified of a UPS-detected power failure. (For information about the new ":shutdown" command, see the SHUTDOWN: NEW CI COMMAND article elsewhere in this Release 7.5 Communicator.)

One of the new configuration options specifies the amount of time (called the "powerfail grace period") that a power failure must last in order for the UPS Monitor to cause the user's "powerfail command file" to begin execution.

Another new option allows the user to specify, by its file name, the particular MPE/iX command file to execute in response to a power failure that meets the "grace period" time duration specification.

A third new configuration option allows a System Manager to override the standard behavior of the UPS Monitor subsystem in case of a power failure that nearly exhausts a UPS device's battery backup power capacity. Normally, the UPS Monitor intentionally causes a special System Abort in case of a "low battery charge" condition reported from a UPS device. The reason for this is to ensure that no disk device is in the midst of writing data to the disk surface at the time at which the disk device actually loses its AC power, because modern SCSI disk devices are susceptible to writing garbled data if they are performing a write operation when power disappears. To prevent this possibility, the UPS Monitor aborts the running system ahead of UPS battery exhaustion time, so that existing disk write operations either complete or abort (harmlessly), and no new disk write operations are started, prior to the time when a disk device actually loses its power. The new configuration option allows a brave-hearted and insistent HP e3000 System Manager, who strongly believes that she/he can manage the disk situation effectively by other means, to prevent this intentional system abort, and allow the HP e3000 system to "keep running" even after a UPS device has announced "low battery charge - approximately two minutes of power remaining".

NOTE: Use of this "keep running" option is entirely at the discretion and responsibility of the HP3000 System Manager. Hewlett-Packard DOES NOT RECOMMEND the use of this option, and can not assure users that disk-stored data will not be corrupted if this option is used.

New UPS Monitor Configuration Options

The following new configuration options are made available by this enhancement. Each option requires one new line in the UPS Monitor's configuration file, either the default UPSCNFIG.PUB.SYS configuration file, or another UPS Monitor configuration file that you have established via UPSUTIL's Newconfig command.

Powerfail Command File

This option allows you to establish your own MPE/iX command file to be launched into execution by the UPS Monitor whenever there is a UPS-device-detected AC power failure whose duration exceeds the time specified as the "powerfail grace period" time.

The powerfail command file can be any valid MPE/iX CI command file within the "standard" MPE/iX file system - i.e., it is a file with a file name of the form myfile.mygroup.myacct. Its content is not known to and not restricted by the UPS Monitor/iX subsystem. UPS Monitor/iX simply passes this command file by name to the MPE/iX CI (as a subordinate process of UPS Monitor/iX) whenever conditions for command file execution are met.

The syntax for the powerfail command file option is:


  powerfail_command_file = file.group.account [; parm1 parm2 ... parmN]


  powerfail_command_file   =  $null

The first format above specifies a particular file to be the powerfail command file. Parameters (parm1.. parmN) are optional; if they are specified, then they are passed to the MPE/iX CI "as is" at the time at which the powerfail command file is launched into execution.

The second format simply states explicitly that no powerfail command file is to be used by UPS Monitor, and is no different in its effect from not having any "powerfail_command_file = xxx" command in the UPS Monitor configuration file at all.

Powerfail Grace Period Delay Time

This option establishes the amount of time (in seconds) that a UPS-detected AC power failure must endure before the UPS Monitor begins to execute the user's "powerfail command file". The grace period allows an amount of time to pass, to give AC power a chance to return, before causing any "powerfail command file" actions to take place, so that short-duration power failures does not cause system shut downs (and/or whatever other actions, such as aborting jobs and sessions, closing volume sets, etc., may be specified within the user's "powerfail command file").

The permissible range of times for the "grace period" is from zero seconds (no time at all; begin to execute the user's "powerfail command file" immediately upon AC power failure detection) through a maximum of 1800 seconds (30 minutes), and is based on the nominal 15-minutes at full power load reserve capacity of the UPS device's battery pack.

The syntax for the powerfail grace period option is:


  powerfail_grace_period   =   nnnn

where nnnn is the desired integer number of seconds of "grace period", from 0 through 1800.

While it doesn't really make sense to specify this configuration option unless there is a companion specification of the "powerfail command file" option, there is no harm in doing so. If there is a configuration of the "grace period time" but no specification of a powerfail command file, then the UPS Monitor takes no action following the expiration of the "grace period" time ... it may as well never have been specified.

Powerfail Low Battery Action

This option allows you to override (at your risk!!) the UPS monitor's default action of causing a special System Abort in case, during an AC power failure, a UPS device signals "low battery charge" condition. You can force the system to continue running even after the UPS has notified the system of its "low battery charge" condition by using the "keep running" form of this configuration option.

The syntax for this option is:


  powerfail_low_battery   =  system_abort


  powerfail_low_battery   =  keep_running

Summary: Sample UPS Monitor Configuration and Powerfail Command Files

Here is a sample UPS Monitor/iX configuration file, to illustrate the configuration file options being provided in this enhancement, as well as the prior "routing of ** RECOVERY FROM POWERFAIL ** messages" option.


  upscnfig.pub.sys
  powerfail_message_routing = all_terminals
  powerfail_low_battery     = system_abort
  powerfail_command_file    = mypfail.mygroup.sys;
      inventory_data_set, orders_data_set
  powerfail_grace_period    = 300

And the companion "powerfail command file" (mypfail.mygroup.sys) might look as follows:


  parm volset_one, volset_two
  tellop ------------------------------------------------------------
  tellop UPS POWERFAIL -- powerfail command file "mypfail.mygroup" starting
  tellop ------------------------------------------------------------
  comment
  tell @S -----------------------------------------------------------
  tell @S  Please LOG-OFF IMMEDIATELY, system going down due to
  tell @S  UPS Power Failure.
  tell @S -----------------------------------------------------------
  comment
  pause  60
  vsclose  !volset_one
  vsclose  !volset_two
  shutdown  system
  tellop ------------------------------------------------------------
  tellop Powerfail command file "mypfail.mygroup" completed execution.
  tellop ------------------------------------------------------------

UPSUTIL Enhancements

The UPSUTIL utility program (UPSUTIL.MPEXL.TELESUP), which helps to manage the UPS subsystem by providing an online "query and control" interface to UPS Monitor/iX, has been enhanced to correspond to the new features of UPS Monitor/iX. UPSUTIL's "status" display has been expanded to show the status of the new configuration options for powerfail command file, powerfail grace period, and powerfail low battery action. In addition, a new command, RESETPFAIL, has been added to UPSUTIL. It clears-out status display information pertaining to any prior execution of the "powerfail command file".

Status Display Enhancements

a sample of the new version of the UPSUTIL status display. The enhancements to the status display are marked with "arrows and numbers" in the right margin, and are explained below.

Figure 5-1 Status Display

Powerfail Command File Name and its status: This part of the status display shows the name of the current powerfail command file (if any; it may be $null), and its status with respect to its validity as a powerfail command file (either "OK" or "has error").

Powerfail Command File Parms: If the UPS Monitor configuration file command (powerfail_command_file = filename [; <parm1> ... <parmN>]) that specified the current powerfail command file did include some parameters, then those parameters are listed here. If not, then this part of the status display will be blank.

Powerfail Grace Period: This part of the status display shows the current powerfail grace period, in seconds, if one was specified in the UPS Monitor configuration file. Otherwise, zero appears here.

Powerfail Grace Timer: This part of the status display shows the current state of the powerfail grace timer, either "Not Running" (no powerfail is in progress, timer is not running), or "Running "(AC power failure in progress, grace period timer is running), or "Completed" (AC power failure lasted longer than the grace period, timer has run-out). If the timer has completed, then the date and time of completion is shown on this line.

Powerfail Command File: Similar to the powerfail grace period status display, this line shows the current state of the powerfail command file: either "Not Running" (no powerfail, or powerfail has not yet exceeded the grace period time), or "Running" (power failure in progress and has exceeded the grace period; the user's powerfail command file is now being executed), or "Completed" (powerfail command file execution completed). If it completed, then the date and time of completion are shown on this line.

Action on UPS Low Battery: The configured action of the UPS Monitor in case of UPS "low battery charge" condition is shown here in the status display. It may be either System Abort or Keep Running.

RESETPFAlL Command

RESETPFAIL is a new command added to the UPSUTIL command set, to support the new "powerfail command file" capability. All it does is to reset (clear) the information in the UPSUTIL status display that pertains to the Completed state and date/time of completion of the powerfail grace period timer and the powerfail command file execution. That is, the RESETPFAIL command changes the states of the Powerfail Grace Timer and Powerfail Command File in the UPSUTIL status display from Completed to Not Running, and clear-out the dates and times of completion of the Powerfail Grace Timer and Powerfail Command File.

The motivation for this capability is to preserve the Completed states and dates and times of completion of the most recent executions of the Powerfail Grace Period Timer and Powerfail Command File until the system manager has had an opportunity to observe them. Having observed them via the STATUS command, then the system manager can use the RESETPFAIL command to clear them back to a "dormant" condition (Not Running), waiting for the next system power failure to be recorded.

For Further Information

For further detailed information about the new UPS Monitor enhancements, including a full discussion of the UPS Monitor Configuration File and Powerfail Command File, refer to the new chapter on UPSUTIL in the MPE/iX System Utilities Reference Manual, which has been added as part of Release 7.5 manual updating.

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