Solaris@Home Part 2: Being eco-responsible while saving a buck or two

Today, we'll see what we can do at home to be more eco-responsible. As you know, I've retired my trusty, old Qube and my cute little NSLU2 (now sold to my neighbor) in order to consolidate my home server needs into a real machine, a Sun Java Workstation W1100z, named "Condorito".

The power of having a real machine at home to serve my different entertainment gadgets has its cost, and that is, quite literally, the cost of electric power. In my Spam, I found two coupons for a german electronic retailer, so I decided to buy me a Watt-meter and check for myself. The combination of Qube (with it's standard 20GB disk, plus an extra 80GB one), and NSLU2 and an external 200GB USB disk, plus a small switch consumed an average of about 40 Watts. This doesn't sound like much, but in Munich, we pay about 16 Euro-cents per kWh. So, my little old gear consumed 40W \* 24h \* 356d / 1000 = around 342 kWh a year. That's 55 Euros a year (about $66) just for having some stuff in the basement!

So I decided to minimize the power that the new gear consumes, to keep costs under control. I won't try to get below 40W, since the W1100z is much more powerful and can provide more sophisticated services for me. But I want to save as much as possible, so I don't leave too much money on the electro-table. Here's what I measured on my W1100z:

With a total of 3 disks, monitor attached and no optimization, but also no load, it sucked more that 135 W of power. Just sitting there. Too much. But fear not: We can help that:

  • Some Solaris-loving laptop users among my colleagues came up with a few tips on how to improve disk power management. What works for saving battery power on a laptop also works for saving money at home:

    • Stop fsflush from rolling the log every second by saying set tune_t_fsflushr=300 in /etc/system.

    • Stop fsflush from pushing inode updates out so frequently by putting set autoup=300 in /etc/system.

    • Encourage the disks to go into standby mode earlier by specifying standby=30; in /platform/i86pc/kernel/drv/ata.conf.

  • Thanks to Casper Dik's frkit, Solaris can now (experimentally and at your own risk) support the AMD Opteron PowerNow! Technology. The powernowd deamon automatically adjusts CPU frequency and voltage (and thereby power consumption) to the load on the system.

  • I also discovered that the graphics card consumes less if you boot the system without any monitor attached.

After trying out all of the above (many thanks to Casper for helping me getting powernowd to run on W1100z), my W1100z power consumption went down to just below 80 Watts! So by just optimizing a few things in software, my system now consumes more than 55W less, saving me more than 75 Euros ($90!) a year. The difference between the lowest power and the highest power state in the AMD Opteron Model 150 when idle on my machine was around 30 Watts alone. Each disk (I now have 4) consumes about 5 Watts when spinning and the rest (5-10 Watts) is the graphics card when not doing anything. You see, eco-responsibility is not just about tree-hugging, it can save you a lot of money in just a year's time!

Boy, I wish I had one of the new Sun Fire T2000 servers at home. Not that I would be able to actually consume it's throughput power with my handful of networked gadgets, but just because it's so energy efficient, so elegant and so well designed...

Back to my W1100z: I may have doubled my power budget, but I now have increased my CPU capacity about ten-fold, added 250GB of extra disk space plus I now have a nice, enterprise grade operating system at home to play with. Tune in to my next episode in the Solaris@Home series where we'll find out some interesting uses of ZFS and how it relates to digital TV...

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what did you do exactly to get powernowd working on w1100z?

Posted by bbr on December 20, 2005 at 11:45 PM CET #

Hi bbr, actually, powernowd didn't work yet out of the box. I asked Casper for help and he logged into my machine to get it working. I suspect that powernowd didn't know how to interpret the W1100z's ACPICA tables. I'll ask him what he did exactly and if it will be included in later official releases of powernowd.

Posted by Constantin Gonzalez on December 22, 2005 at 01:37 AM CET #

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