Commentary: Is Fibre Channel still in your future? Michael Krieger of Ziff Davis Market Experts takes a look at the new options for SAN deployment.
Although much has been written about Storage Area Networks (SANs) over the past
few years, only one in three IT shops has yet to deploy SANs, according to the
April 2003 Ziff Davis Market Experts study on storage purchasing. Most of those
SANs have been deployed in larger organizations, and for the most part, these
storage devices are connected to each other and the systems they serve using FibreChannel
wires, switches and routers.
Although FibreChannel, which solved the problems of distance limitations on
SCSI cabling between disk and server, has been around for years, it is a very
different networking infrastructure than is used for most of the rest of IT’s
networks – namely Ethernet and TCP/IP. Although there are many benefits
of having a separate network for storage, including better performance and easier
troubleshooting, since you don’t have to separate out the network traffic
from the storage traffic, there has been a significant downside: finding and
retaining IT staff who understand how to keep FibreChannel storage networks
happily running, as well as the additional investment in another network –
and the additional hardware costs incurred in the switching gear to connect
it all together.
But SANs aren’t the only way to get the benefits of networked storage.
Network Attached Storage (NAS), which has been around even longer than SANs,
is a quick, easy way to get additional file servers up and running on an existing
TCP/IP Ethernet network. NAS devices can literally be installed in minutes,
don’t require any special cabling or a new network, and are, usually,
less expensive per gigabyte of disk, to deploy. Still, you have to be careful
how you connect it – if a NAS device is attached on heavily used network
segment, the storage traffic can impact the LAN traffic and vice versa. Also,
for applications that demand block-level access to disk storage, such as Oracle
or MS-Exchange databases, NAS devices won’t deliver the performance that
good old fashioned direct attached storage (DAS) in the server cabinet offers.
Internet SCSI (iSCSI) adds to the somewhat confusing array of choices. With
the advent of gigabit Ethernet (gigE), and the imminent availability of 10 gigabit
Ethernet, our old friend Ethernet now offers raw performance in the same ballpark
or better than FibreChannel (which typically runs at one or two gigabits/second).
Just as FibreChannel offers a way to extend the distance between disk drives
and their associated controllers and servers, iSCSI takes the same SCSI protocols
and encapsulates them in Ethernet packets over TCP/IP, which mean you can now
get the benefits of a SAN, including support for block-level transfers, without
having to budget, staff for, and maintain a whole new network to get those benefits.
If you’ve already gone the FibreChannel route, then not to worry –
new generations of FibreChannel adapters, switches, and directors are coming
with even faster speeds. But for the majority of IT shops out there who haven’t
gone the SAN route yet, and who are still feeling the budget pinch that the
current economic climate has thrust upon us, there is now another route to explore,
an Ethernet-only SAN.
Does this spell hard times ahead for FibreChannel? Not in the short term –
in fact most FibreChannel switch vendors are adding iSCSI support to their hardware,
just as companies like Cisco have added FibreChannel capability to their network
switches. But for companies with limited IT budget and a need to get access
to high performance, block-level SAN storage, iSCSI may be the way to go.
Michael has been involved in various disciplines in the information technology field for more than 25 years. His background and experience in product development, marketing and sales give him a unique perspective on how and why companies succeed in the technology marketplace. Before joining Ziff Davis Market Experts, he was a senior VP for marketing at FutureLink, a large ASP based in Southern California. He previously was VP of marketing for Hitachi Data Systems' server product line, and also was a senior product manager for AST Research's server and data communications product lines.
His entrepreneurial experience includes founding Solution Business Systems, a developer of manufacturing software for IBM midrange systems. He was also VP of product development at Techland Systems, one of the industry's first creators of micro-to-mainframe emulators.