A:No, the error is not serious. Unfortunately, the documentation in the area of master/slaves is not very detailed, and for that reason, your slave setup is not totally correct as explained below.

On master machines, we modify /etc/rc.d/init.d/halt to re-invoke apcupsd with the --killpower option (actually the script apccon- trol is called). This causes the UPS to send the codes to the UPS to make it power off.

On slave machines, these modifications should not be made to the /etc/rc.d/init.d/halt script since the slave has no connection to the UPS.

To eliminate the problem, on all your slave machines, either re- store the original halt file, or simply delete all the lines containing

***apcupsd***, which were inserted by the apcupsd installation pro- cess.

Q:To test apcupsd, I unplugged the UPS to simulate a power outage. After the machine went into the shutdown process I plugged the UPS back into the commercial power source. This caused the shutdown process to hang after the daemon tried to shut-off the ups. Have you run into this problem, and if so do you have a remedy?

A:Normally, once the shutdown process has begun, we cannot stop it, though there is some code that tries to do so, we don’t consider it a very good idea – how do you stop a shutdown that has killed off half of the daemons running on your system? Most likely you will be left with an unusable system. In addition, when apcupsd is re-executed in the halt script after the disks are synced, it tries to shut off the UPS power, but the UPS will generally refuse to do so if the AC power is on. Since we cannot be 100% sure whether or not the UPS will shut off the power, we don’t attempt to reboot the system if we detect that the power is back as it might then get caught by a delayed power off (at least for Smart UPSes).

Q:After running apcupsd for a while, I get the following error: “Serial communications with UPS lost.” What is the problem?

A:We use standard Unix serial port read() and write() calls so once a connection is made, we generally have few problems. However, there have been reports that APC’s SNMP Management Card can cause serial port problems. If you have such a card, we suggest that you remove it and see if the problem goes away. It is also possible that some other process such as a getty is reading the serial port.

Q:When apcupsd starts, I get the following error: “attach shmarea: can- not get shm area: Identifier removed.” What is the problem?

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UPS control system specifications

APC UPS (Uninterruptible Power Supply) control systems are vital components for ensuring uninterrupted power supply and protecting critical equipment from power interruptions, surges, or fluctuations. Designed by Schneider Electric, APC UPS systems are renowned for their high quality and reliability. They utilize advanced technologies and features to suit diverse applications, from home offices to large industrial settings.

One of the main features of APC UPS systems is the ability to provide backup power during outages. This is achieved through a battery system that activates immediately when the mains power fails. This seamless transition minimizes downtime and ensures that electronic devices continue to operate, protecting data integrity and equipment lifespan.

Another significant characteristic of APC UPS systems is their intelligent management capabilities. Most models come with PowerChute software, which provides users with real-time monitoring of power conditions and the status of the UPS. This software allows for graceful shutdowns of connected devices during extended outages, thereby preventing data loss and damage to devices.

APC UPS systems also incorporate advanced technologies such as Automatic Voltage Regulation (AVR). AVR technology ensures that the output voltage remains stable by correcting minor fluctuations without switching to battery mode. This not only prolongs the battery life but also provides a consistent power supply to the connected equipment.

Thermal management is another critical aspect of APC UPS control systems. The design often includes efficient cooling systems that prevent overheating, ensuring optimal performance and longevity of the unit. Some models feature EcoMode, which reduces energy consumption and lowers operational costs by working at high efficiency only when battery backup is not required.

APC UPS systems are designed with scalability in mind. Users can easily add more batteries or connect additional UPS units to accommodate growing power needs. Features such as hot-swappable batteries and modular design facilitate easy upgrades and servicing without interrupting power supply.

In terms of connectivity, APC UPS products often feature multiple options including USB, RS-232, and network management capabilities. This enables users to connect remote management tools and integrate the UPS with existing IT infrastructure.

In summary, APC UPS control systems deliver reliability, efficiency, and advanced technology features that cater to a wide array of power protection needs, making them a trusted choice for individuals and businesses alike.
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