Foraging for storage
When Ron Czarnecki, a network administrator with the city of Arvada, Colo.,
began his search for a data-storage solution about 18 months ago, he learned
a simple lesson about storage-area networks (SANs). Money talks.
Czarnecki was seeking an alternative to traditional server-attached
storage that would reduce maintenance headaches and provide a scalable platform
for storage growth. He was anxious to investigate SANs and issued a request
for proposal to Compaq Computer Corp., Dell Computer Corp., XIOtech and
"EMC called us to ask how much money we had to spend," Czarnecki recalled.
"We told them about $50,000 to start. They never called back."
In the end, Czarnecki deployed a XIOtech shared storage array described
by the vendor as a "SAN in a box." Although the solution is not a pure SAN
— a network of heterogeneous storage devices and heterogeneous servers — he is pleased with the acquisition, which he believes will solve both present
and future storage requirements for the city.
At his recommendation, the Arvada Police Department recently deployed
two more arrays from the vendor, a Seagate Technology Inc. company. One
array will serve as a disaster-recovery mirror for the original platform
fielded by Czarnecki.
Elsewhere, county and city government IT organizations are having similar
experiences. They are learning an almost mathematical truism: Burgeoning
data-storage requirements plus limited budgets does not equal a SAN. Fortunately,
other storage solutions — including shared arrays, network-attached storage
and homogeneous vendor storage networks — are available to meet their needs.
Doing the Math
According to Joe Butt, senior analyst with Forrester Research Inc.,
Cambridge, Mass., mathematics is at the heart of slow SAN adoption rates
in small to medium-size organizations. He said any organization, regardless
of its size, can expect to pay seven to 10 times the cost of the storage
devices themselves to deploy them in a SAN.
The explanation for high SAN costs, Butt said, is equally simple: SAN
deployments require time, staff and expertise — "all of which may be lacking
in smaller IT shops, such as those of state, county or local governments."
Additionally, the more heterogeneous the infrastructure — the more
diverse the types and brands of servers and storage devices that must be
interconnected in a SAN — the greater the difficulty in getting the current
generation of SAN products to work, Butt noted.
Those difficulties are not unique to government, and they underscore
the problems with SANs.
In general, small organizations might be well served by a small storage
network using products from a single vendor end-to-end. Such SANs, he said,
are often less difficult to deploy and offer some of the scalability and
manageability features that are promised by larger solutions.
"In most cases, however, the organizations having storage problems already
have heterogeneous storage and server environments," Butt said. "They need
a more manageable storage infrastructure, but they are reluctant to deploy
a SAN because of cost [or] interoperability issues, or because they simply
don't have the people to deal with it."
Many of the complexities of current- generation SANs derive from the
use of high-speed Fibre Channel as the link to interconnect servers and
storage devices with switching equipment. The Fibre Channel protocol remains
a mystery to many prospective SAN users, Butt said, and its comparative
youth as a standard contributes to interoperability difficulties among SAN
equipment vendors and deployment headaches for users with heterogeneous
IP-Based SANs on the Horizon
Butt foresees a jump in SAN deployments once new storage networking
protocols that use Gigabit Ethernet and TCP/IP networks are introduced to
the market. One such protocol under development by the Internet Engineering
Task Force (IETF) — called iSCSI — enables block-level storage data to move
across traditional IP-based Ethernet networks, making it easier and less
expensive to deploy than Fibre Channel, he said.
This view is shared by Robert Passmore, an analyst with Gartner Inc.,
Stamford, Conn. He said iSCSI-based SANs could leap over Fibre Channel SANs
technologically by providing networks that operate at 10 gigabits/sec before
Fibre Channel could offer comparable capabilities. He noted that iSCSI SANs
are rapidly becoming available, citing IBM Corp.'s new IP Storage 200i
series disk array as an example.
Numerous host bus adapter and storage management vendors, including
Adaptec Inc., are also preparing products for delivering IP-based SANs this
year. In addition, vendors ranging from NetConvergence Inc. to Cisco Systems
Inc. are preparing switching, routing and gateway technologies that will
enable storage traffic to flow across IP networks.
Another key advantage of IP-based SANs will be lower overall networking
costs, according to Lauri Vickers, a senior analyst at Cahners In-Stat Group,
Scottsdale, Ariz. She notes that the cost per switch port to deploy Fibre
Channel is currently about $1,400, compared with about $750 per port for
Gigabit Ethernet. Ethernet switching costs are falling more rapidly than
Fibre Channel costs because of the difference in the numbers of ports installed,
Anne Skamarock, senior analyst with Enterprise Management Associates
Inc., is less bullish about the IP-based SAN market. "I have only heard
of a few vendors working on iSCSI SAN products," she said, and those vendors
typically are not targeting enterprise storage requirements. "The IBM solution,
for example, is targeted at small to medium-size organizations. I was kind
Storage vendors are the first to acknowledge that SANs are still evolving
and will become more accessible with time.
"A couple of years ago, a SAN solution was successful only with people
who absolutely needed a SAN," said Paul Ross, director of network storage
marketing for EMC. "It has only been in the last year that the concept of
SAN has begun going mainstream."
However, new challenges have emerged as a result of the increased popularity
of SANs. "People want to use more complex fabrics, combining many different
storage platforms with many different servers," Ross said. "It is a challenge
to get all of the components of a heterogeneous SAN to work together at
the same time without breaking. Since we own any problem when customers
buy our equipment, we are working to make sure that configurations pass
our quality assurance tests before we approve them."
According to Ross, that philosophy led to the recent announcement by
EMC that the company was qualifying several SAN configurations that would
include storage products from EMC and other vendors. The company is exercising
the same careful testing before releasing IP-based SAN solutions. Although
it continues to offer SANs based on Fibre Channel, EMC is "working hard
with Cisco Systems and the IETF IP Storage Working Group to make sure that
iSCSI becomes a viable interconnect," Ross said.
Jon Pollock, director of storage marketing for Dell, agrees that iSCSI
and other IP-based SAN technologies hold promise, but he questions the view
of some analysts that SANs are too costly to deploy until IP-based SANs
arrive. Dell offers its own SAN — which includes Dell servers, host bus
adapters, switches and storage products — as a plug-and-play SAN solution
that, in Pollock's view, "targets exactly the type of environment that you
find in government" as well as in small to mid-size organizations.
"Dell is a leader in this kind of setting, which requires the sharing
of 250G of storage between two to four servers," he said. "We provide a
completely redundant configuration for less than $50,000. Our solution is
in its fourth generation and is Fibre Channel down to the disk drives."
The debate about the cost and manageability of SAN solutions might push
some organizations to consider alternatives.
Competition to entry-level homogeneous SANs comes in the form of shareable
storage arrays from XIOtech, Hitachi Data Systems Corp., EMC and others,
as well as network-attached storage (NAS) platforms from Network Appliance
Inc., Procom Technology Inc. and many others. A NAS device attaches directly
to a general-purpose network, providing servers and clients with direct
access to its data.
Homayoun Yousefi'zadeh, senior product manager for Procom, Irvine, Calif.,
is bullish on network-attached storage. "Today, NAS delivers things that
SAN cannot: support for heterogeneous server operating systems, true data
sharing, a familiar network infrastructure, plug-and-play installation and
others," he said.
Procom is a part of a movement within the industry to add some SAN capabilities
to NAS, such as block-level access to data. NAS currently supports data
access in the form of files rather than discrete blocks as required by some
transaction-processing applications and databases. The result of those efforts,
he said, will be the creation of "a NAS/SAN hybrid that will capture the
benefits of both technologies."
Even before those hybrids arrive, NAS makes "a strong case on a price-performance
basis as a data-management solution that can leverage existing standards
and architectures in storage and networking," said Michael Alvarado, storage
networking marketing manager for Network Appliance.
NAS addresses problems ranging from shortages in employee skills — IP
network-savvy job candidates are more plentiful than Fibre Channel-savvy
types — to the needs of knowledge workers in small to medium-size organizations.
"The storage appliance metaphor has a particular appeal to knowledge workers
who need to share data across networks as a key to business success but
need a storage solution that doesn't require a large IT organization to
deploy or manage," Alvarado said.
"The XIOtech array centralizes our data and allows it to be shared among
the four servers — running [Microsoft Corp.'s Windows] NT, Unix and [Novell
Inc.] NetWare — that are connected to it," he said. "When we need to connect
more servers, we will decide whether to put in a SAN fabric switch or just
deploy another box. If we run short of capacity, we will either change out
disk drives for higher-capacity drives or deploy another box. It is the
easiest way to go — a one-stop shop."
Toigo is an independent consultant and author specializing in business automation
issues. He can be reached via his Web site at www.toigoproductions.com.