Monday, March 27, 2006

EXPECT DOUBLE DISK FAILURES WITH ATA DRIVES - Dave Hitz - NetApp Founder

After reading Daves' blog you have to wonder if NetApp keeps any of their critical accounting data or sales data on ATA drives. Dave goes on to say - Bottom line, using ATA drives without double protecting RAID is questionable. As drives grow, I suspect that it will become a requirement even for Fibre Channel drives.

Perhaps Dave is suggesting that the best protection against a poor implementation by the manufacturer of the storage subsystems and drives is to waste storage space. I guess that makes sense for the storage companies, because to protect yourself you need to waste storage space which means they sell more storage. But according to their sales and marketing campaigns their systems are extremely reliable. So why is Dave Hitz suggesting that customers buy more protection against disk failure?

Either their complete systems are reliable out of the box or they are not. Don't worry though, Zerowait knows how to make NetApp systems reliable. Zerowait provides affordable alternatives to NetApp for Service, Support and Upgrades.

1 comment:

Dave Hitz said...

Actually, using RAID-DP doesn't waste any extra space, and since it's bundled with the base system, there's nothing extra to buy.

Here's why it doesn't waste space. With regular RAID, we recommend that users create 7 disk RAID groups with one parity disk. With RAID-DP, we recommend that users create 14 disk RAID groups with 2 parity disks. The math works out that RAID-DP is way safer than regular RAID even with 14 disk RAID groups. So no extra overhead.

I don't know whether NetApp itself stores any critical accounting or sales data on ATA (or SATA). With RAID-DP, I am now comfortable with the reliability of ATA for that kind of data, but ATA performance isn't as good, so that might be an issue. I'm pretty sure we use ATA drives for the mirrored copy of critical data.

Why support ATA drives, given that they are less reliable and not as fast? Because they are CHEAPER!

Of course, Mike might point out that if you buy them used, they'll be cheaper still! :-) (Hi Mike.)