IBM's recent launch of solid state disc storage products for the
enterprise was an endorsement of a much misunderstood technology.
Could it be time to take this seriously?
When IBM launched a range of
solid state disc (SSD) technology, the company had problems
generating interest. This despite the fact that it would complement
one of the hottest new technologies, virtualisation in the
enterprise, with SSD that could fit into its blade servers.
"Virtualisation is hot. But we have been cold on SSD," admitted
Charlie Andrews, IBM's director of system storage products, "we
want to get into more conversations about SSD."
A solid-state drive (SSD) is a data storage device that uses
solid-state memory to store persistent data. Unlike the
flash-based memory cards used in digital cameras and mobile phones,
a SSD emulates a hard disc drive, thus easily replacing it in most
applications. An SSD using static random access memory (SRam) or
dynamic random access memory (DRam) (instead of flash memory) is
often called a Ram-drive.
The two types of SSD, Flash and Ram, can be deployed as
enterprise storage media. Ram is more stable and has a better
reputation for endurance than Flash. But Flash is quicker. The
fundamental flaw in Flash is that it wears out after several
writes, However, manufacturers have created memory controllers,
which spread the allocation of data to this medium. This has led to
a flood of new products coming on the market.
SSD may prove a revelation in enterprise storage. It is,
arguably, a better technology - being faster and more resilient
than the hard discs that are traditionally deployed.
It is also more compact, so it could possibly help the
datacentremanager make a saving on office space. Last, but not
least, it uses less power, which will help IT managers stick to a
corporate social responsibility agenda, even if they do not recoup
all their investment when the electricity bill comes in.
Clive Longbottom, service director of Quocirca, says, "If you
have IT systems, which involve high levels of input output, you
might have to upgrade the disc technology every two years anyway,
as the market moves so quickly,so provided you have the money, you
might find that SSD is a good investment. It certainly gives
something to those companies than need a competitive
advantage."
SSD can simply be acquired as a replacement for normal hard
discs. Companies such as Hewlett-Packard, EMC and Hitachi are all
producing SSD Flash products for use as storage arrays (akin to
Redundant Array of Independent Discs storage arrays).
Another option to consider is to use SSD not as a replacement,
but as a complement to existing technology, advisesHamish
Macarthur, managing director of storage analyst Macarthur Stroud.
One option is for enterprises to attach Flash or Ram to boards,
which are then connected via a PC card to the backplane of a
server. These boards, which could be provided as memory or fast
storage, then offer as a separate entity. Though this idea is not
without its challenges (there are data protection issues) it does
at least mean that storage, kept separately outside of the server,
is easier to protect.
Finally, there is the option offered by
Texas Memory and latterly EMC, which is a rack-mounted system
of Ram or Flash-based SSD, which can hook up to a server, or
network-attached storage (Nas), or be part of a storage area
network (San) configuration.
Some large enterprises are already calculating that this
technology can lower their total costs of ownership. "We look at
the whole life cost of the hardware," says Geoff Connell, the CIO
for the London Borough of Newham. "So if it requires less cooling
or draws less current then we would be prepared to pay more."
But SSD is not there yet. "We would need many SSDs to give the
same capacity as a disc. This negates the power savings," he
says.
Clearly the cost of memory is going to make SSD less attractive
froma total cost of ownership perspective compared to hard disc
drives.
However, as storage analyst Macarthur Stroud predicts, the price
will come down rapidly in the next two years. "Virtual environments
will demand a new way to meet storage challenges. And the cost of
SSD will be more competitive," says Hamish Macarthur, found of
Macarthur Stroud. SSD is already an option in some laptop
computers. It is only a matter of time before server computing
starts to benefit.
What is SSD?
The original usage of the term solid-state (from solid-state
physics) refers to the use of semiconductor devices rather than
electron tubes, but has in this context been adopted to distinguish
solid-state electronics from electromechanical devices as well.
With no moving parts, solid-state drives are inherently less
fragile than hard discs, so they arealso silent (unless a cooling
fan is used) as there are no mechanical delays, they usually enjoy
low access time and latency.
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