It started out an uneventful day, the third day in an entire week that I expected to spend in my home office. That’s something of a rarity in recent times. I was enjoying it, catching up on matters around here, and addressing tech support calls as they arose. I was on just such a call when, to my considerable surprise, the power went out.
The sudden loss of power is not enough to disrupt my phone call beyond my own expression of surprise. As I’ve documented elsewhere, I’ve taken steps to ensure that critical infrastructure around here is on a UPS. To paraphrase Frank Herbert, “The electrons must flow.” In fact, it occurred to me that this afternoon was an opportune time to ascertain just how sound my planning had been.
In the home office all the critical bits are powered via a 1500 VA Belkin UPS not unlike the one pictured below. In fact, it’s that very model.
After Hurricane Ike last fall I found that the units batteries, the two year old original ones, were non-functional. So, I replaced them with aftermarket replacements at a cost of around $50. Given than the UPS was only $120 brand new that was about as much as I was willing to spend on new batteries. In fact, the logic behind replacing the batteries has more to do with keeping the unit in service and out of the trash. In any case, the batteries in the unit are less than 6 months old.
From the time the power went out and I first heard the UPS alarm all my core network stayed online as expected. What was plugged into the office UPS? Here’s a list:
- Siemens Speedstream DSL modem
- Soekris Net4801 router running m0n0wall
- Netgear 24 port gigabit switch
- HP T-5700 thin client running Astlinux
- HP T-5700 thin client running FreeNAS/SlimNAS
- La Cie Network Disk NAS (5 drives, 2.5 TB)
- Siemens S675 DECT base
- Aastra midspan POE insertor
- Polycom Soundpoint IP650 desk phone
The very fact that I shy away from traditional server platforms, preferring low-power embedded systems, shines when utility power is lost. All this gear ran for around 45 minutes before the UPS gave its last gasp and shut down. After about 10 minutes with utility power off I manually shutdown the NAS. Only my laptop was still running, and not needing access to the files on the NAS.
You might notice a few things logically missing from the list of devices on the office UPS. Some of my core network infrastructure is in fact in a closet in the house, where I have a second, smaller UPS unit. That UPS is only 900 VA and supports the following devices:
- Lindy 16 port 10/100 switch
- Netgear WRT-2000 acting as a draft N Wifi access point
- Linksys SPA-2002 ATA for the home phones
- Snom m3 DECT base
I don’t keep every desk phone running on UPS power as I don’t have a POE switch, just one POE inserter. I keep my desktop Polycom and one DECT cordless system running for flexibility. It happens that I have some Siemens DECT phones in-house so I had two DECT bases running this afternoon. DECT stuff is really great under these circumstances since they draw so very little power.
When the office network finally went down I still had wifi connectivity to the laptop, but no internet acess since the DSL circuit was down. The very fact that the wifi was still up says that the house UPS kept its devices running longer than the office UPS.
In my case the point of the UPS is not to support indefinite run-time with loss of utility power. That would be impractical. It’s intended to let me ride through brief loss of power without feeling any effect at all. For outages for more than 30 minutes I would expect to need a local, long term power source, ideally a standby generator.
After Hurricane Ike I put some serious investigation into standby generators. I know that to sustain our home we need between 13-17 kw. That would run literally everything in the house indefinitely, even the 4 ton central air conditioner.
Houston can be insufferable without air conditioning so there’s little point in going with a smaller generator. If utility power is to be out for a long time, like ten days after Ike, then running the air conditioner will make a dramatic difference in our quality of life during that period. In the two weeks post-Ike we were very lucky that the weather cooperated, and it wasn’t very hot. I could have been so very much worse for the entire city.
I hope that one day we will take the next step and install the standby generator and associated transfer switch. That project is awaiting about $6,000 of budget. Until that day comes our current UPS arrangement has proven adequate. By the time I returned from a late lunch this afternoon the utility power was restored and everything was back to normal.