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.
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. 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.
I hope YOU aren't ever buying for MY company.
Rest assured, I won't be. -frank _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
