Linked by Thom Holwerda on Fri 18th Sep 2009 13:40 UTC, submitted by Robert Escue
Hardware, Embedded Systems This is an article which discusses the increase in storage capacity while performance and hard error rates have not improved significantly in years, and what this means for protecting data in large storage systems. "The concept of parity-based RAID (levels 3, 5 and 6) is now pretty old in technological terms, and the technology's limitations will become pretty clear in the not-too-distant future " and are probably obvious to some users already. In my opinion, RAID-6 is a reliability Band Aid for RAID-5, and going from one parity drive to two is simply delaying the inevitable."
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Robert Escue
Member since:
2005-07-08

Is it? I can't think of too many companies that are betting the farm on SATA storage in terms of performance or reliability. How are 7,200 RPM SATA disks going to compare to a 4 GB Fibre Channel array using 15,000 RPM disks, there not. SATA only beats FC in terms of capacity and cost.

SSD's are also immature technology that is only beginning to be integrated into devices like Sun's Unified Storage System 7000 series arrays, and even then they are being used as cache, not primary storage. While this might not be the case in five to ten years, SSD's are not quite ready for prime time data center use just yet.

Reply Parent Score: 4

bannor99 Member since:
2005-09-15

Is it? I can't think of too many companies that are betting the farm on SATA storage in terms of performance or reliability. How are 7,200 RPM SATA disks going to compare to a 4 GB Fibre Channel array using 15,000 RPM disks, there not. SATA only beats FC in terms of capacity and cost.


I wasn't separating SATA from SSDs in this context.
I was implying that despite the high cost of SSDs, you
could balance that against using a cheaper interface and still win on almost all counts.

However, there is no reason why SSDs can't be made with SAS interfaces.
And don't be knocking SATA hard disks too much. I seen data from several sources that they have lower failure rates than some of the higher end drives, even if they're not as fast.


SSD's are also immature technology that is only beginning to be integrated into devices like Sun's Unified Storage System 7000 series arrays, and even then they are being used as cache, not primary storage. While this might not be the case in five to ten years, SSD's are not quite ready for prime time data center use just yet.


SSDs have been around a long time ( see articles at www.storagesearch.com ). It's not a matter of being ready for the data center, it's the enterprise resistance to change and the slower adoption of newer tech by the big players.

Reply Parent Score: 1

Robert Escue Member since:
2005-07-08

There is a large amount of consumer grade SSD's which might work well for those who do not expect high throughput I/O and a long life cycle. When you start paying $20,000.00 and upward for a storage array, everything changes.

I am sure I am not the only one who thinks that SSD's are not ready and waiting for early adopters and risk takers in the field to shake them out before recommending them as part of a replacement or upgrade solution for existing storage.

Reply Parent Score: 3

jwwf Member since:
2006-01-19

Is it? I can't think of too many companies that are betting the farm on SATA storage in terms of performance or reliability. How are 7,200 RPM SATA disks going to compare to a 4 GB Fibre Channel array using 15,000 RPM disks, there not. SATA only beats FC in terms of capacity and cost.


If your budget (in money, power, and space) is truly unlimited, you're right. But what if you can choose, say, mirrored SATA or parity raid fibre given the constraints at hand? What if you can choose SATA that is half full, versus fibre at 80% ? What if you can afford more SATA spindles? I don't think it is that clear cut given the normal constraints.

Reply Parent Score: 2

Robert Escue Member since:
2005-07-08

Budget does come into play. Our history with SATA storage here has not been a good one. We bought storage from a vendor that after six months decided to get out of the SATA storage game and dropped support for the devices. We now have over a hundred 500 GB SATA drives that we pulled from the arrays and junked the rest.

We also have SATA solutions from other vendors (NetApp, HP) and the jury is still out. Power, AC, and space do come into consideration but some of the people I work with also expect a level of performance that SATA might not meet, plus factor in the idea of using SATA over SCSI and FC makes some uncomfortable.

Most of the server rooms I have worked in are near or over capacity for power and AC, but new ideas are usually the hardest sell.

Reply Parent Score: 2