On Sun, Jan 24, 2010 at 10:38 AM, Frank Cusack <fcus...@fcusack.com> wrote:
> On January 23, 2010 8:23:08 PM -0600 Tim Cook <t...@cook.ms> wrote: > >> I bet you'll get the same performance out of 3x1.5TB drives you get out of >> 6x500GB drives too. >> > > Yup. And if that's the case, probably you want to go with the 3 drives > because your operating costs (power consumption) will be less. Nope. > > > Are you really trying to argue people should never >> buy anything but the largest drives available? >> > > No. Are you really so dense that you extrapolate my argument to an > extremely broad catch-all? There are other reasons besides cost that > people might want to buy smaller drives. And, e.g., if your data set > isn't that large, don't spend money for space you don't need. > > The post that I was responding to claimed smaller drives *allowed* him > to get to raidz3. I challenged that as incorrect. It's the larger > drives that *require* raidz3 because resilver time is longer. So far > I've seen no argument to the contrary. Just a side argument about > cost which I happen to disagree with. And a followup side argument > about planning for redundancy which I also disagree with. > You're calling me dense and you think the sole purpose of him using raid-z3 is resilver time? Hey guys, let's throw self-healing out the window when using consumer drives because it's cheaper per GB to buy a larger drive size. You're trying to convince the OP not to use raid-z3 because you either haven't read up, or find no benefit to some very real, and very useful features he will see with it. > Let's say you need 3TB of storage. That's a lot for most home uses. > The actual amount doesn't matter as the costs will scale. So you > buy 5 1.5TB drives. 4 (2+2) in a raidz2 plus a hot spare. For the > sake of this argument, let's say you've done the math and raidz2 > meets your redundancy requirement, based on time to resilver. More > likely, a home user has not done the math but that's besides the point. > > Now let's do it with .5GB drives. A quick survey shows me they come > in at about a 10% discount to the 1.5TB drives. I'm being generous > because I can't even find .5GB drives, but I see that 320GB drives > are about 10% less. If you want to get even "cheaper", 250GB drives > are about 50% less cost than 1.5TB drives (which by my argument, which > you refute, makes them 3x more expensive but whatever). > > So with .5GB drives you need 6+3 drives -- because the smaller drives > "allows" you to get to raidz2, plus a hot spare. That's twice as many > drives, however you are only paying 10% less per drive. PLUS with this > many drives you now need a pretty big chassis. Plus your power costs > are now quite a bit higher. > > Please put together a scenario for me where smaller drives cost less. > 10%? I'm not sure where you shop, but no. The cheapest 500GB is $39.99. The cheapest 1.5TB is $97.99. http://www.zipzoomfly.com/jsp/ProductDetail.jsp?ProductCode=10010737 http://www.newegg.com//Product/Product.aspx?Item=N82E16822148516 $359.91 for the 500GB drives. $391.96 for the 1.5TB drives. -- --Tim
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