Mike Karp, Senior Analyst, Storage Management Practice,
Enterprise Management Associates

What's Driving Storage?
A multitude of trends are driving storage expansion today, all of which are, if not intuitively obvious, at least factors that storage professionals have seen before:

• Technology
  • A-to-D conversions
  • High-definition applications (everything from CT scans to HDTV)
  Analog-to-digital conversions are escalating as consumers and businesses are digitizing more and more of their content and data. The most familiar example of this is family pictures that used to be captured on film but are now saved electronically. There's also been a fundamental shift within already-digitized areas of technology, such as CT scans and X-rays, which are now saved with far greater granularity than ever before.
  
  
• Regulatory/Legal Requirements
  Regulatory and legal demands play a key role in promoting digital information storage, as searching for specific files or data is much easier when they are stored digitally.
  
  
• Digital Archiving
  Ultimately everything in a company's archives can be considered intellectual property, and if that property has not been digitized it can very difficult to take full advantage of its value.
  
  An obvious example: When a famous citizen dies, MSNBC knows that CNN can put together an obituary within ten minutes by calling up information on the deceased. MSNBC must be able to do the same at least as quickly, and putting metadata tags around digitally stored data is far faster and more efficient than sifting through analog video tapes.
  
  
• Saving Data is Universal
  Finally, the basic rule of storage is that everybody saves everything.

What's Driving SAS?
Most obviously, SAS is moving up to six gigabit per second (6Gb/s) speed, but that's not all:

• 6Gb/s SAS moves into servers and external storage
• SAS as a fabric moves into blade and rack environments
• SAS roadmap goes beyond 2013 with 12Gb/s SAS
• SAS moves into SMB space, enabling tiering and build-up
• Tiering continues to grow in the mid-range and enterprise markets

SAS Ecosystem Expands
The ecosystem that SAS supports is becoming quite broad indeed, and veteran storage professionals understand that for emerging technology standards to become de facto standards, there must be an ecosystem built around that technology. As Figure 1 shows below, a SAS ecosystem now exists in virtually every conceivable area.

Figure 1: SAS Ecosystem is Expanding

SAS Participation Swells
Virtually every vendor that a company might need in order to operate in a SAS environment is already there and participating vigorously. The list* reads like a veritable Who's Who of the IT industry:

Fujitsu, HP, Amphenol, DataDirect Technologies, Aristus Logic, Accusys, Adaptec, LSI, Bridgeworks, Finisar, STEC, Condre Storage, Ciprico, Emulex, Hitachi, IBM, Broadcom, AIC, ATTO Technology, Dell, AMCC, Maxim, Nimbus Data Systems, Promise Technology, Intel, Marvell, PMC-Sierra, Seagate, JMR, Solid Access, Qsan, SanBlaze Technology, Tabernus, Catalyst Enterprises, Infortrend, StorCase Technology, Xyratex, Molex and more...

*All registered trademarks and trademarks are the property of their respective owners.

Scaling Up, Out & Down
Within the last three months a 1TB drive was announced at SNW, and both 500GB and 750GB SAS drives are already shipping. What's more, 3Gb/s SAS is ramping up in the marketplace after having been available from vendors for quite some time. While 6Gb/s SAS is not yet ready for market, it's only because vendors are busy catching up on the products needed to ensure that both initiator and target-side solutions are available.

It's interesting that SAS vendors are making sure that SAS not only scales up and scales out, but also that it scales down. As a result, there are now four-port adaptors for modest storage environments, while for scale-out applications, vendors offer adaptors with as many as 28 ports.

SAS Growth Curve - I/O and ROC Controllers
The sales figures below come from LSI and represent real-world product shipments actually purchased by customers. As can be seen, from the second quarter of 2006 through the first quarter of 2007, well over three million I/O controllers and more than one million RAID on a Chip (ROCs) sold.

• Production shipments: LSI (2Q06-1Q07)
  • SAS I/O: 3.46M units
  • SAS ROCs: 1.0M units

10K RPM and 15K RPM SAS HDDs in 1Q08
SAS has already achieved substantial market legitimacy for a variety of reasons noted earlier. Consequently, the HDD sales figures shown in the graphic below are all fairly impressive. Equally important, if we were to draw these results as a curve, the numbers are going up and to the right (always a good trend!).

Figure 2: SAS HDD Sales are Growing

Note that the above sales figures come from the vendors themselves. In the Fujitsu and Seagate charts, purple represents SAS, yellow/white indicates Fibre Channel and light blue depicts parallel SCSI. As the pie chart on the left shows, first quarter shipments from Fujitsu heavily favored SAS (throughout all of its enterprise storage lines).

The pie-chart on the right represents Seagate's estimate of the total industry enterprise market split from all HDD suppliers this year, with SAS representing the lion's share of drives.

Now consider drive shipments from a different link in the value chain, that is, drives not shipped by drive vendors but by Hewlett Packard (both drives in DAS attachments and in DAS configurations and arrays). Once again the line (here in pink) representing SAS as rising, while the blue line denoting parallel SCSI is going down. The bottom yellow line represents parallel ATA and SATA, lower-end drives that appear in Enterprise IT rooms.

SAS Projections Align with Sales Figures
Looking again at sales numbers from vendors in the graphs below, the figures on the left from LSI Ingenio show that parallel SCSI (represented here by Ultra320) is declining; in fact, looking through to Q107 it appears to be declining almost to the point of nonexistence. By contrast, the Q1-07 percentage share of SAS shipments confirms the dominance of SAS in the LSI Ingenio product mix.

Figure 3: SAS Increasing Share in Enterprise Storage Mix

While the graph on the upper right omits the Y axis (showing Hitachi's unit sales), the important point is not the numbers, but rather the quarter-over-quarter growth trend that the graph illustrates. Yet again, the curve goes up and to the right, indicating greater volumes with each passing quarter.

In the Seagate graph on the lower right, yellow/white represents Fibre Channel, light blue denotes parallel SCSI and purple (the lion's share) indicates the piece of the pie owned by SAS.

SAS' Future: SFF
Clearly SAS is growing, almost to the point of omnipresence in most aspects of enterprise and even midrange IT environments. While the data below is from Fujitsu, it's likely similar to information which other vendors would provide if pressed. As can be seen, SAS represented two out of three enterprise drives that Fujitsu shipped.

Small form factor (SFF) 2.5-inch disk drives represent about a third of these shipments. But SFF shipments have grown substantially over the last two years, and it's expected that the 3.5-inch form factor that many have come to take for granted will actually flatten. Within a year it may even see negative growth.

• Fujitsu (1Q08):
  • SAS represented ~2/3 of all enterprise HDDs
  • SFF SAS was approximately 1/3 of these shipments
  • SFF SAS shipments have grown over 570% since early 2006
  • Industry will continue to migrate to SFF SAS

How the Stars Aligned
If one looks at how this all happened, it's clear SAS came along at just the right time—the stars were in alignment. Parallel ATA had been in essence, legislated out of existence by several vendors, not the least of whom was Intel. And parallel SCSI was running out of gas for a number of reasons, but there was no practical way to extend beyond the Ultra320 phase of SCSI. Meanwhile data just kept on accumulating...

Figure 4: Confluence of Factors Boosted SAS Success

Fibre Channel seemed to be relatively contained in its ability to scale throughput. Furthermore, the sheer quantity of parallel SCSI in the marketplace (mostly in DAS configuration) was a solid indicator that people wanted to stick with SCSI. Though some criticize SCSI as problematic, it has always been "the devil that we know." If storage professionals don't embrace it, at least they can control it – and for the most part it does what they want it to do.

And now SFF drives have arrived, ensuring that SAS will be driving a great deal of market decision making. Small form factor storage has a number of interesting aspects to it; for example, because it's small it requires less power while enabling an enormous quantity of data to be centralized in a relatively small amount of space. It also has compelling implications for those focused on the greening of the data center.

The Challenges that Lie Ahead
To be sure, there is some bad news; specifically, the sheer amount of data involved is making backup archiving and recovery extremely challenging for enterprise customers. This is why data de-duplication, for example, has become such a hot item in the storage business.

RAID will be severely challenged over the next several years because, although more bits will fit on a disk, there has been relatively little improvement in the ability of those bits to escape failure. The more bits on a disk, the higher the likelihood of failure, and by extension the greater the likelihood of lengthy RAID rebuild times.

There are ways around this, but they require some serious rethinking on the part of everybody involved. And the management of all this is yet another challenge, as operational expenditures can be brutal—somewhere between four and eight times that of hardware costs in the IT room. That's a significant challenge, and as the volume of data grows the challenge will only increase.

The good news is that none of this has anything to do with SAS. Most of these problems stem from the mix of huge amounts of data, a new generation of very large drives and old RAID technologies. SAS has already proven its value to an impressive number of storage professionals, and there's still plenty of opportunity for even greater market success because the body of data that must be stored is growing every day.

Mike Karp has spent over 20 years in storage, systems management and telecommunications. Mike's focus at Enterprise Management Associates is storage, storage management and the methodology that brings these technologies into the marketplace. He has extensive tactical and strategic experience in business development, strategic alliance and channel programs, marketing, and industry research and analysis.

During his career, Mike has written twenty-three books covering operating systems, CAD/CAM, editors, systems installation, and systems operation and administration. He is the co-author of Storage Solutions: A Buyer's Guide. Currently, Mike is an author for the Storage in the Enterprise newsletter for Network World Fusion.

Mike blogs weekly on storage, Web 2.0 and social interaction at www.internetevolution.com

www.enterprisemanagement.com
http://www.scsita.org