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Follow UsBy Anne Stuart
For
something with no physical properties, information certainly takes up a lot of
storage space. And that same intangible asset generates plenty of very real
headaches. Businesses of every size know all too well about the difficulty of
managing an amorphous resource that, worldwide, is growing by nearly 30 percent
a year.
Not
surprisingly, there's widespread demand for a safe, effective and relatively
inexpensive way to house all that data — ideally, a solution that can expand in
a snap as a company's information-storage needs multiply.
HP
Labs researchers are working on an answer that could replace the inflexible
storage systems of today with a modular system, designed to quickly accommodate
a fast-growing organization's changing storage needs.
not monolithic
Modular,
not monolithic
"Traditional
storage systems are large, monolithic and expensive," says Alistair
Veitch, a researcher in the HP Labs Storage Systems Department. "Every
manufacturer has multiple product lines. They're targeted to different market
segments and different specialties. Often, you've got separate teams designing
separate product lines, and none of them use the same hardware and
software."
As
a result, when customers outgrow one storage system, they typically must start
over as they move up to the next one.
HP
already offers a relatively standardized approach provided via its
next-generation storage architecture, the HP StorageWorks grid, which uses some
elements of the lab's modular, system
The
ultimate goal: to give organizations the ability to focus on using the
information they have stored, rather than on managing the storage itself.
Smart
Cells
Researchers
began work on what became their modular system about three years ago.
"We
looked at whether we could build a system that would scale from the low end to
the high end and have all the features that you want," says Veitch, senior
technical lead and project manager. "We asked whether there's some way we
could use off-the-shelf hardware and software, rather than following the
expensive, time-consuming tradition of customizing new technology for each new
product line," Veitch continues. "And," he adds, "we looked
at whether we could make that system for less money."
Based
on the team's ongoing work on the project, the answer to all of those questions
appears to be "yes." Essentially, their system relies on small,
rack-mounted storage appliances consisting of disks, CPUs, storage adapters and
network cards. Together, each of these constitutes one modular storage unit
called a "brick" or "smart cell."
Cells
can be added as needed. "By adding more cells, you get more capacity and
performance," Veitch says.
Rapid
response to demand
A
software program "glues" cells together so they function like a
single array, or, as Veitch puts it, "one very large pool of storage"
that can be allocated as needed. The storage load is automatically rebalanced
whenever units are added or subtracted.
The
result: a storage system that, unlike traditional disk-array storage systems,
scales quickly and easily in response to demand. IT administrators can either
automatically or manually deploy, expand or reconfigure their storage systems
without disrupting service or affecting performance. And they can do so at
relatively little expense because the use of common hardware components keeps
costs down.
Upgrades
of the product line are easy, notes Beth Keer, storage systems department
manager. "You can adapt to changes in technology over time — improvements
in interconnects, for instance — fairly rapidly."
Different,
but effective
Researchers
initially worried that their ideas might represent too dramatic a departure
from traditional storage systems.
"We
thought there might be a little psychological resistance to something that
looks so foreign," Keer says. "But because of its scalability, it
actually has a familiar feel."
Upgrades
of the product line are easy, notes Beth Keer, storage systems department
manager. "You can adapt to changes in technology over time — improvements
in interconnects, for instance — fairly rapidly."
International,
multi-disciplinary team
Like
many teams at HP Labs, the group is both international and multi-disciplinary.
Each of its nine members represents a different country and a variety of
technical areas. (Veitch is from New Zealand; Keer was born and raised in the
United States and other team members hail from Argentina, Brazil, Denmark,
Greece, India, Japan and Scotland.) Researchers' technical specialties
encompass a lot of territory as well, and include distributed systems,
availability, performance, algorithm design, modeling, engineering, code writing,
operating systems, networking and storage.
That
breadth of experience and knowledge helped them tackle the numerous technical
challenges they faced in developing their solution.
One
problem had to do with addressing component failures, which required replicating
the data between cells. But incorporating backup protection into systems is a
complex undertaking involving some tradeoffs, Veitch says. "Designing in
hardware redundancy adds a lot to the costs and complicates the software."
Ultimately,
the team struck the right balance, designing their solution to respond even
better to failure than standard storage systems. When a piece of hardware on a
traditional disk-array system fails, that system typically loses a large
percentage — often half or more - of its performance capability. But with the
HP Labs system, if one component fails, the others take over, allowing the
system to function with little or no loss of performance. Administrators can
also easily remove and replace malfunctioning hardware.
Different
cells for different needs
The
team built its prototype using standard rack-mounted servers. Because of the
limited number of disks supported by these first systems, the team is now
experimenting with newer designs that will incorporate larger numbers (up to 12
disks) in a single compact package.
One
of the advantages of the experimental architecture is that various aspects of
the hardware are flexible - you can have a cell that has relatively more disk
drives per CPU units, for instance, which would be more appropriate for bulk or
archival storage. Other cells may have more memory for higher performance.
"What's
exciting now is the huge opportunity that's ahead of us," she adds,
"both in terms of the business engagements and all the research threads we
can explore. It's probably more than we have the time and resources to do, so
we need to prioritize. But that's a good position to be in."
If
one fails, others carry on
Efficiently
handling such heterogeneity is another key research area. Veitch anticipates
that cells will come in a variety of storage sizes - from smaller, four-disk
models containing a few hundred gigabytes at the entry level, to about a dozen
or more drives containing up to a few terabytes.
To
add additional storage, "You just plug in a cell and connect it to the
network," Veitch says. "Then you go to your management console, where
you're looking at the whole system. You'll see how just how much useable space
is there."
The
Labs experimental solution also uses different methods of replicating data to
make sure it's always available, such as using an algorithm that provides
mirroring of data in three locations. "That way, if one fails, the other
two can carry on quite happily," Veitch says.
Continuing
research
Although
some HP StorageWorks grid products now use early versions of smart-cell
technology, the HP Labs team continues developing the concept.
Current
experiments involve increasing system scale. "Right now, we can scale to
20 or 30 cells," Veitch says. "We'd like to go beyond that and build
some really big systems."
How
big? The team envisions architectures one day containing hundreds, perhaps
thousands of cells — enough to build a virtual warehouse big enough to meet the
storage needs of even the most prolific business.
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