Introducing the UPS and UPS Monitor/iX Software

• In a minimal UPS-based system, the degree of power failure protection is equivalent to that provided by the battery backup unit. You can, however, add more UPS devices to the system and provide reserve power to selected peripherals. Depending upon how much of the system is provided with UPS power, it can run a partial or full workload non-stop through limited periods of AC power failure.

• The UPS contains a serial I/O communications interface that, in conjunction with UPS Monitor/iX software, notifies the system operator of any problems. Like the battery backup hardware that the UPS devices replace, a system-wide power failure recovery message is broadcast to all active user terminals and to the console upon the return of power following a failure. In addition to console messages, the UPS Monitor/iX software also posts a variety of status and warning messages to the system log files which you can review and analyze to evaluate system performance.

To configure a UPS

You can use one of two configuration methods to add UPS devices to a Series 9X8 systems. For the first or only UPS, which is attached to the third serial port on the system's LAN/Console I/O interface card, you do most of the configuration with SYSGEN. For additional UPS devices, which are attached to a DTC serial I/O port, you add them to the configuration primarily using the NMMGR program. (As the final step in this second method, you will cross-validate the configuration files with SYSGEN.)

On a Series 991 or 995, all UPS devices are attached to the system via a DTC serial I/O port. As a result, you use NMMGR to configure them and then, as a final step in the process, cross-validate the configuration files with SYSGEN. (If you have configured user terminals on a DTC, the method will be very familiar.)

To configure the first UPS on a Series 9X8

The first UPS device on a Series 9X8 system is attached to the third port on the LAN/Console I/O interface card. To perform most of the configuration, you use SYSGEN's I/O Configurator. Once you have done so, you use NMMGR to set the baud rate (which you cannot do in SYSGEN) and then cross-validate the configuration.

To configure the first UPS on a Series 9X8, do the following:

	NOTE: Each UPS device, and only a UPS device, MUST have its device class name set to HPUPSDEV during I/O configuration. Otherwise, the UPS Monitor software will not be able to initialize and communicate with the UPS device(s) correctly.

To configure a UPS connected via a DTC port

On a Series 9X8 system, all UPS devices other than the first one are connected to your computer system via a DTC port. On a Series 991 and 995 system, all UPS devices (including the first one) are connected via a DTC port. In both cases, you use the NMMGR program to add them to your system configuration. (If you have configured user terminals on a DTC, the method will be very familiar.)

To configure a UPS connected via a DTC, do the following:

To use UPS Monitor/iX software

Once you have configured UPS devices on the system, they will automatically be monitored by the UPS Monitor/iX software. This software causes the UPS devices to emulate the traditional battery backup method of system powerfail handling and recovery and, in addition, provides system console messages and system log file entries describing UPS hardware conditions.

The UPS Monitor/iX process behaves in one of two ways, depending on the system on which Release 5.0 of MPE/iX has been installed:

	NOTE: UPS monitoring is event number 148 in the system log files. The default is ON (i.e. UPS hardware conditions are recorded in the files) regardless of whether the system has UPS power fail protection or not. In the latter case, when no UPS devices have been configured, the system log files will receive and record two UPS-related messages each time the system starts: one indicating that the UPS Monitor/iX process has been launched and a second message which says that no UPS devices are found in the I/O configuration.

System behavior when AC power fails

Whenever input AC power to any UPS device fails, the UPS hardware switches to internal battery operation to continue to deliver output AC power to the computer equipment. No actual power failure occurs at the computer equipment itself and, as a result, the SPU continues to operate. However, the actual behavior of the system will vary depending on how much of the system equipment is provided with UPS power.

In the minimal case, where only the SPU and any Remote Busses receive UPS power (and assuming that disks are external to the SPU), the system is most likely to appear to be dormant (like a traditional battery backup method system) because the system can not make progress once the disks lose power and spin down. The system will simply enter its "idle loop", waiting for disk I/O operations to complete, and that won't happen until AC power returns and the disks spin up again.

But in expanded UPS coverage systems, where some or all of the disks receive UPS power, the system may continue to run to some extent. Again, it depends on what resources the system needs to perform its workload. Batch jobs that only need CPU, memory, and disk I/O can continue to run undisturbed. Processing that requires tape or printer or terminal I/O will be blocked if those peripherals do not have UPS power. UPS Monitor/iX issues a warning message to the system console to notify the operator that the particular UPS (identified by its LDEV number) has reported to the system that its input AC power has failed. In the following example, UPS Monitor/iX reports and power failure and a recovery shortly thereafter:

   :showtime

   FRI, AUG 13, 1993, 11:27 AM

   :

   :11:27/50/UPS LDEV 102 reports loss of AC input power. (UPSERR 0033)



   **RECOVERY FROM POWER FAIL**



   11:27/50/UPS LDEV 102 reports AC input power restored. (UPSWRN 0036)



   :

UPS Monitor/iX also writes a system log file entry that denotes the input power loss to the UPS device. Read “To enable logging of UPS activity” and “To review UPS activity recorded in the system log file”, later in this chapter for more information.

System Behavior When AC Power Returns

The behavior of the system when AC input power returns to the UPS is very similar to that of the battery backup method systems. One of two things will happen: a recovery from power failure (if AC power returns before the UPS battery that backs up the SPU becomes exhausted) or a system crash.

If AC power returns before the UPS battery becomes exhausted (up to fifteen minutes when starting with fully charged UPS batteries; less if the batteries were already partially discharged), then the system recovers from the AC power failure and resumes normal operation. In this case, UPS Monitor/iX displays a message on the system console, posts an entry in the system log files, and broadcasts the following message to all active user terminals:

   ** RECOVERY FROM POWERFAIL ** 

If the UPS battery that powers the SPU becomes exhausted before AC input power returns, then the system really does lose AC power and crashes. In this case, when AC power does return and the UPS turns on again, the system reboots just as if it used battery backup.

To enable logging of UPS activity

The UPS Monitor/iX program posts UPS status and alarm messages to the system log files. If system logging for the UPS Monitor/iX (which is event number 148) is turned on, you can review the messages to troubleshoot your system configuration and evaluate system performance.

As the default, event 148 is ON. To verify that it is or, if necessary, to turn it on, do the following:

To review UPS activity recorded in the system log file

UPS Monitor/iX status and alarm messages are recorded in the system log files as event number 148. You can use the LOGTOOL utility to review entries in the system log file about the performance and condition of UPS devices on your system. To do so, follow these steps: