Quoting Stan Hoeppner stan@hardwarefreak.com:
David Jonas put forth on 1/14/2011 2:08 PM:
Raid10 is our normal go to, but giving up half the storage in this case seemed unnecessary. I was looking at SAS drives and it was getting pricy. I'll work SATA into my considerations.
That's because you're using the wrong equation for determining your disk storage needs. I posted a new equation on one of the lists a week or two ago. Performance and reliability are far more important now than
total space. And today performance means transactional write IOPS not streaming reads. In today's world, specifically for transaction oriented applications (db and mail) smaller faster more expensive disks are less expensive in total ROI that big fat slow drives. The reason is that few if any organizations actually need 28TB (14 2TB Cavier Green drives--popular with idiots today) of mail storage in a single mail store. That's 50 years worth of mail storage for a 50,000 employee company, assuming your employees aren't allowed porn/video
attachments, which which most aren't. And that's assuming a platter squeezing in 1TB of data at 7200RPMs doesn't get a comparable performance improvement to a higher rotational speed on a lower volume platter... Hell for the price of a single 250gb SSD drive, you can RAID 10 TEN 7200 RPM 500GB SATAs.
So while, yes, my 10 drive SATA RAID 10 ONLY performs 166MB/sec with a 'simplistic' dd test, In reality I just don't think Joe User is going to notice the difference between that and the superior performance of a single SSD drive when he POPs his 10 3k emails.
Rick