Wednesday, August 27, 2008

Coming soon - All UPS units are NOT created equal !

The cheap part of me overruled my brain and I made the grave mistake of buying a lesser know (but still popular brand) UPS. Being a good little Geek, I dutifully left the unit plugged in over night to charge the batteries. The next day I was shocked to discover that the case of the UPS was hot to the touch. Heat means power loss. What I discovered made me hot under the collar, and I'll never buy a cheap UPS again.

Data on this is coming up.

Tuesday, August 26, 2008

Another inexpensive to operate home server: HP EX470

I had mentioned earlier that I was using a Thecus N5200 as a home server to provide power efficient 24/7 storage for all my photographs, videos and music files. After almost four years of use I had amassed so many photographs (sports photography is a hobby and a typical game will consume 700 or so photographs) that I was starting to worry about losing the entire Thecus box (not to a single disk failure which the RAID array would recover from, but losing the disk controller or box -- recovering files from dead RAID arrays borders on the impossible).

As luck would have it, HP had announced their MediaSmart Server based on Windows Home Server. The 500 GB EX-470 seemed a perfect entry vehicle to start with. I purchased one from Newegg and populated it with two additional 1 TB drives.

Performance testing indicated that the throughput of the HP box was about 2x the speed of the Thecus, with almost no difference between read and write speeds. Finally I had a server that was taking advantage of my Gigabit Ethernet network.

In addition to being a darned fast storage device the server also acts as an automatic backup device for all my windows based machines. Finally I don't have to nag my wife and kids about backing things up to the server -- it all happens automatically. With our desktop and laptop computers taken care of, the only thing missing is support for our two Macs (which can't use the automatic backup).

Add the fact that the box is setup for media sharing, and has full time virus scanning, and you have a winner product.

Power monitoring indicates that the EX-470 pulls about 70 watts 24/7, slightly more than the Thecus consumption of 60 watts. However there is a good reason why. Microsoft has determined that RAID arrays are too difficult for the average home user to maintain -- especially when something goes wrong (like a controller crash). They designed the Windows Home Server to store all the files in a fashion that allows you to plug the drive into a standard controller should the need arise and easily find the files. They also provide automatic "mirroring" of the files to another disk should you enable that feature for a directory (so you mirror just what you need, not an entire disk).

These two features require a bit more disk access on the part of the EX-470, which may need to move a file to balance storage, or to duplicate it if it is mirrored. That translates into a bit more power consumption over time.

The cost to operate the HP EX-470 with three drives is $0.31 a day or $9.53 a month.

What can be done about your server costs? (Get rid of that old PC)

A lot of Geeks have servers that run 24/7. Often built out of left-over computer parts, Geeks typically brag about how little they spent on their server, yet fail to consider the cost of electricity. That old box of parts can cost big dollars compared to purpose-built boxes.

I had assembled just such a server class machine in a full size tower. Based on an AMD Athlon 64 3400+ CPU, it ran three 500 GB drives in a RAID 5 configuration. The Asus motherboard provided on-board video, which generally was not used. This was my pride an joy, hosting my music and photo collection. It was also my 'home' server and ran 24/7.

Imagine my shock when I metered the power usage and found that it was pulling 400 watts 24/7. That server was costing me about $1.75 per day (or $55 a month) to operate.

To make matters worse, because it was a perfectly acceptable desktop as well, I would occasionally use it for other purposes. Inevitably a blue-screen-of-death would develop that would cause me to have to do an ungraceful shut-down. That generally caused the RAID array to have to recover from a fault -- a process that would take over 24 hours to complete.

It was clear that the classic solution to a home server was simply not economical in this instance. So I began to research purpose built NAS devices. Most of them suffered horrible performance issues (typical of the low cost disk box with a USB and Ethernet interface sold by just about all the disk drive manufacturers). A few vendors, like Thecus and Buffalo came out with some interesting devices, and I finally settled on a Thecus N5200.

At the time, the Thecus N5200 was the fastest RAID array on the market (unless you compared it to hardware that cost 10 times as much that was intended for corporations), especially in terms of write performance. It was physically small (about a half-cubic foot in volume), and allowed up to 5 SATA drives. Because it was purpose built to be a RAID box, I suspected the power supply would be optimized, and it was.

Extensive testing of the Thecus N5200 indicated that the cost to operate was $0.26 a day ($8.17 a month). This was 1/6 the power needed for my original box. In fact, based on power savings alone, I paid for the original cost of the Thecus in 13 months (I reused the same three disk drives from my big-iron server). Before the end of 2008 I will have saved an additional $1600 in operating costs.

What did I gain by using a purpose built NAS? An increase in write speed of about 4X. An increase in read speed of about 2X, start-up that is automatic (no console needed), a whole bunch of desk space, and a much lower power bill. What did I give up? Well I can't use it as a spare computer anymore, but that just avoids crashing the RAID array anyway.

Monday, August 25, 2008

What does my network cost me to run? ($0.55 a day)

A network to a Geek is like air to a human -- essential for life. And while networks come in all sizes and flavors, one thing they share in common is they are running 24/7. And like all things Geek, there is a cost associated with that.

I've measured the power consumption of my primary network components and found that my basic network and printing resources cost me an average $0.55 per day (or $17 per month). Given my past experience with mid-sized desktops, I was pleasantly surprised, especially since this figure includes the power necessary to keep a large capacity UPS up and running in addition to a Thecus N5200 NAS and 24/7 OfficeJet printer.

The equipment that is part of my 24/7 network is as follows:

  • APC BR1200 UPS (I like my network to stay up for hours!)
  • Motorola 5101 Surfboard Cable Modem
  • Apple AirPort Extreme (Gigabit) Router
  • Netgear ProSafe GS108 8-port Gigabit Switch
  • HP 7300 OfficeJet Multifunction Printer
  • Thecus N5200 Raid 5 NAS with 3 drives

So how much does a desktop computer cost to run 24/7? (About $1 per day)

I could put on my engineering hat and say "it depends", which would be a typical Geek answer, because it does depend on a lot of things. However such an answer is not very useful to most people.

I can tell you that my #1 suspect in increased power consumption was my work PC, a Compaq Evo D500 desktop of mid-range performance (circa 2001 -- what can I employer is thrifty), with dual 19 inch displays (Dell LCDs). After several months of monitoring, I can tell you that in round figures my PC and displays pull about 200 watts idling and 300 watts running full tilt. The cost per day is $1.06 on average, or about $32 per month.

By the way, the PC is left on 24/7, but does not sleep. The LCDs go to sleep after 5 minutes of lack of activity, and the hard disk spins down after 15 minutes. I'm at my work PC about 10 to 12 hours a day.

So are you shocked at how much leaving a PC connected costs these days? I certainly was. To put that in perspective, it represents 10% of my total power bill on a bad month, and 15% of my average bill. Don't let someone tell you keeping a computer on 24/7 doesn't cost much!!

Similar tests on server class PCs running 24/7 were even more discouraging. The typical power consumption was about 400 watts per hour, or about $1.75 per day.

So now that I know, what can I do about it? To some extent, not much. Several applications I have need to run 24/7 so it isn't a good target to shut down entirely, but I do unplug things over the weekend and on holidays. (Every little bit helps). The real answer may lie in upgrading to more modern equipment. Future Greener Geek measurements will tell all !

How do you measure power?

One definition of the word power is the "amount of energy required or expended for a given unit of time". As far as the utility company is concerned, they bill you for kilowatts-hours (abbreviated KwH).

What is a kilowatt-hour? 1.0 KwH is using 1000 watts of power for a period of 1 hour.

Because it involves both power (kilowatts) and time (hours) you really have to pay attention to both items. Example: you could use 500 watts (a half-kilowatt) for 2 hours, and the utility will bill you for 1.0 KwH. Likewise, you could use 6000 watts for 10 minutes and you would also be billed for 1.0 KwH.

The utility's power meter keeps a running tally of the total amount of power you consume. The utility charges you for the power you used over the billing period, which is approximately one month. Changes in the climate (how hot/cold, light/dark) and the variability of the billing period (27 to 34 days) can make it frustratingly difficult to compare one month's bill to another.

While the total number is useful, especially in spotting trends, it is too coarse to be of value when trying to do something about the power hogs in your house. To do that you need something called a plug-load power meter. A popular one, just right for the Greener Geek, is the P3 Kill A Watt EZ 4460 meter, which allows you to enter the cost per KwH (18.3 cents here in good-old Rhode Island). A less expensive model (P3 4400) is also available which doesn't tally up the running cost.

The P3 EZ 4460 costs about $38 at, while the less expensive one is about $20 at

How accurate is the P3 EZ? Well I have some pretty fancy equipment available because of my line of work, traceable to the National Bureau of Standards. I can tell you that the P3 EZ that I own is better than 2% on both current and voltage measurements (mine was worse on current) for loads in the 20 to 400 watt range.

What does the P3 meter do for you? You plug whatever appliance (or Greener Geek accessory) into the front of the meter, and it will measure the power consumed for what ever period of time you have it plugged in (it also will record the total time it has been measuring the power).

I recommend measuring whatever device you have for about a week to get a good representation of cost to operate. The reason for this is that the power consumed may vary wildly by use. For example, a laptop with a fully charged battery might only pull 20 or so watts, but that same laptop with a discharged battery might pull 65 watts while the battery is charging.

Welcome to the Greener Geek

Rhode Island is a beautiful place, a scenic wonderland. Often the subject of jokes because of its small size, I can say for a fact that it is number 1 in at least one category -- the highest electrical rate in the continental United States! With a rate change adopted in late July 2008, the standard electrical rate for residential customers is now $0.183 per KWh delivered, higher than all mainland states and second only to Hawaii (also blessed with natural beauty, but thousands of miles away from its #1 source of electricity -- oil).

I design hardware and software to save energy in commercial and industrial buildings, so I have always had an interest in all things "green". I can tell you that I take pride in the fact that as a result of my efforts over the last 3 decades, products that I've designed have reduced the power consumption (and carbon emissions) of tens of thousands of businesses. That's more than enough to offset power-hungry lifestyles of all the blow-hard, do nothing politicians in the country (even Al Gore's annual electrical consumption of 221,000 KwH -- 20 times the national average).

When I first started working from my home about 3 years ago, I noticed a huge increase in my power bill. I directly attributed that to the equipment that I now have hooked up and running 24/7 in my house (various computers and other technology devices). Part of that is that the electrical rate has gone up (in the past decade, I've seen my power bill more than triple in average monthly cost), but also due to increased consumption on my part.

This blog will detail some of my findings concerning power consumption, and may provide some information that is shocking to some.

The bottom line... the power-footprint of our 24/7 lifestyle is a extra-large one and we can all use some help in becoming a Greener Geek.