Tech/Horsepower

I caught this fascinating Dell post through twitter yesterday about 2.5″ SAS hard drive density and speed finally rivaling the 3.5″ SCSI standard. SCSI speeds at half the size+performance benefits is awesome, but I believe Bryan missed a major attraction to the 2.5″ form factor: power consumption.

Recently, I’ve been mitigating power troubles in our data center space. We’re in a great center, but it’s older so I’m subject to a 100 watts-per-square-foot limit. Two racks, total 30sq/ft = 3000 watts total. We’re towing that line hard. When I read about the power requirements in Bryan’s post, I was blown away by the wattage comparison: “~6.2 watts for each 2.5-inch 10K 300GB vs ~17 watts for each 3.5-inch 15K 450GB“. That’s impressive. Then I did the math.

In just my heavy-hitting servers and PowerVault arrays, I have 100 3.5″ 10K SCSI drives, most 300G with a handful of 146G. Using a conservative estimate of 15 watts per drive, that’s 1500 watts – half of my power consumption limit. By migrating to the 2.5″ SAS drives at 6.2 watts I could reduce to 620 watts. That’s awesome. Most of my PowerEdge 2U servers (with 3.5″ drives) consume 200 watts, that’s four more servers I could install. Four.

Now think about those reductions if you’re paying the power bill. Replacing your 3.5″ drives with 2.5″ of the same density could generate extraordinary cost savings and improve your environmental footprint. It’s just a shame I can’t plug and play or easily convert SCSI to SAS, but you better believe as we grow I will be converting.