We're currently looking into upgrading our UPS and possibly having a small petrol generator on site in the eventuality that the UPS battery is used long enough to drain it completely.
Realistically, we can only afford a UPS that would give us around 45 minutes. It's not unheard of for our building to have outages of 4-6 hours. It is very rare though.
What products are available that are capable of sending notification (SMS, automated call, etc.) when a UPS switches to battery power? Some UPS's we've looked at have serial connections. How do you deal with this kind of thing?
The plan is that when the power goes down, the battery takes over and alerts the team. One of us (whomever is on call) drives the the building and starts the generator. Unless of course a notification comes through that the power is back on.
We do currently use Pingdom to monitor uptime of our services. It's just a ping test though so we can't rely on a lost host to explain why it's lost. For example; if the network connection went down and so did the backup link, we would get a notification. That doesn't necessarily mean the generator needs to be started.
Best Answer
The serial comms port is an indication of either an old or a small UPS (unlikely to provide you with the 45 mins of coverage for any notable number of server machines, network infrastructure and peripherals). It has been the state-of-the-art interface around 1995, but has been superseded by SNMP-capable Ethernet interfaces since.
Most of the available monitoring systems are capable of using a custom check or script to get the current UPS state over the serial port (obviously, it would need to be physically connected via a serial cable) or listening to SNMP traps and raising alerts and notifications in various ways - feel free to choose one to your liking.
If you already do have UPSes in place which cannot be upgraded with SNMP cards and have no other means of connecting to the UPS to monitor its status but are using servers with redundant power supplies, you might consider a setup where at least one PSU is connected directly to the mains, while the other(s) is(are) fed through through the UPS. Upon a power failure, you should get a PSU power loss event on the mains-connected PSUs, which you could forward and treat accordingly in your monitoring / notification system.
Note: if you are using your UPS as the single surge protection for your servers, you might want to add an external surge protector to reduce the risk of a potential PSU damage upon voltage spikes in the last scenario.