I have started this thread to summarize some of the experienced users input based on a thread started in October. Some great discussion of optimal hard drive buying patterns developed.

 

Here is some of the input:

 

$/GB needs to include energy costs.  So if a 500GB and 1TB drive each use five watts on average (assuming a typical mix of read, write, idle, and spun down) and power is $0.10/kwh (reasonable estimates, feel free to recalc with better numbers), the energy cost per drive is $22 over five years, meaning that the example of $50 and $125 really becomes $144 ($50x2 + $22*2) and $147 ($125 + $22) so fewer spindles counters some of the upfront cost differential.  Add to that needing a smaller power supply, fewer fans, ... and the cost "savings" of the simplistic calculation quickly disappear.

 

Yeah, I could adjust for NPV to make it a bit more accurate, but interest rates are so low it doesn't make much difference.

 

To be fair, there is a savings re: parity drive since you wouldn't be "wasting" a 1TB drive, just a 500GB, but then we can get into the significant cost penalty incurred when you grow out of the drive limit of the software/case/power/etc. - probably $400+ to build a second system (sans drives).

 

 

Bill

 

In my mind, 3 TB of data is best done with 4 1TB drives

 

 

6 * $69 (500GB drives) + $69 (parity) = $483 + shipping.

3 * $129 (WD 1TB green drives) + $129 (parity) = $516 + shipping

2 * $189 (1.5TB) + $189 (parity) = $567 + shipping

 

Now it costs slightly more but then you need to factor in possible rebates, mechanics (slots/hardware), Power, Heat, Sata Ports.

Last week there was a price drop on the 1TB wd drives to 109 with free shipping.

 

WeeboTech

 

 

 

If you goal was to create a 9T array, here is the breakdown.

 

With 750G drives you would need 12+parity @ $100 each = $1300

 

With 1T drives, you would need 9+parity @ $120 each = $1200

 

With 1.5T drives you would need 6+parity @ $190 each = $1330

 

I'd definitely be tempted to go with the 1.5T. You'd likely not even need an addon controller!

 

bjp999

 

That depends on the price/GB.

500GB @ $70 = 14 cents/GB

750GB @ $100 = 13.33 cents/GB

1TB @ $120 = 12 cents/GB

1.5TB @ $190 = 12.67 cents/GB

 

Doing some fuzzy math (cost of controllers , power supply, etc not taken into account):

500GB vs 750GB -> break even at 4.5TB

500GB vs 1TB -> break even at 2.5TB (nearest common multiple, 3TB)

500GB vs 1.5TB -> break even at 9TB (500GB exceeds unRAID drive limits)

750GB vs 1TB -> break even at 1.5TB (nearest common multiple, 3TB)

750GB vs 1.5TB -> break even at 13.5TB (750GB exceeds unRAID drive limits)

For obvious reasons, going with 1TB will be less expensive than going with 1.5TB at any total storage capacity.

 

At the above price points, 1TB drives offer the best value, but I really don't appreciate the associated storage limitations.

 

ilovejedd

 

 

You have to also take into account how often you need to add drives. if you only add drives one every three months by the time you get to your 4th drive it will be half the price. Then you have to take into drive size increase. Theres not point buying 5 1TB drives this now if you wont fill them up for 12 months as the money it costs will likely be more than replacing the parity and adding less bigger drives later on.

 

If parity could be made up of 2 or more drives then the math is simple. Choose the cheapest per MB drive and upgrade capacity with more drives at the very last second.

 

NAS

 

iNPUT?