The industry consensus is that SMBs will take to it-for cost benefits. But
large enterprises won't rush to replace their fiber channel installations
When the old and complex fiber channel had to die, a new promise-of using
the Internet Prototol in a storage area network over the Gigabit Ethernet-promised
an era of new storage architectures and greater benefits. Not to forget the ooh
aahing over the chea-per new technology!
Even as the storage industry is still polarized into pro and anti-iSCSI
(Internet SCSI) cate-gories, there is one fundamen-tal realization: The
prophecies have largely gone haywire. Yes, IP SAN (Storage Area Network) is
coming, but it is yet to enjoy the market acceptance that many expected.
Enterprises like financial institutions and hospitals, the world over, continue
to bank on fiber chan-nel for high storage per-formance, mission critical
reliability and large complex connectivity.
The hardware components of IP SAN come cheap com-pared to fiber channel. It
opera-tes in a known network, has fewer interoperability issues and is simple.
So why is the adoption rate so slow?
B. Chandrasekhar, country manager with Intransa, feels it is because the
Indian market has always been slow in adopting any new technology. IP SAN is a
relatively new concept. It needs a protocol called iSCSI, which became a global
standard only in 2003. For the last 15 years, people have been using DAS (direct
attached storage) or a fiber channel (FC)-based storage network.
Server vendors were slow to introduce native iSCSI device drivers. Sudhakar
S. Rao, Consulting Director with Hitachi Data Systems India, feels the low rate
of adoption is because the iSCSI is stabilized solely for the Windows and Linux
markets. Besides, there are currently not many IP-based products from the major
storage vendors.
That is a view widely circula-ted. A CIO typically first examines his
differing storage requirements. For storage needs of data-a database, for
example, which is online and needs to be accessed fast-he would, in all
probability, veer towards fiber channel storage. For old data that needs to be
accessed with more time in hand, a more reasonably priced solution like IP NAS
is thought of. George Thomas, country manager with Network Applia-nce, believes
that people will gradually move IP SAN towards more mission-critical
applications.
Country-specific problems could be a hindrance in its adoption too. Says M
Vidyasa-gar, executive VP, Advanced Technology, TCS, "The advan-tage of IP
SAN is that, whatever you would want to retrieve, can be done through the
Internet. This essentially means there is need for very high-speed Inter-net
connectivity at the last mile, and at the enterprise level, which is not
there."
Problems in the way
The implementation of IP SAN needs a significant amo-unt of software
overhead content that has to be executed by the initiating server. "This
software has different eleme-nts, including the requirement for checking lost
packets, interrupt handling on each packet transmitted, integrity check
generation and verifica-tion, and buffer movement of data, among others. In a FC
implementation, this is imple-mented in the hardware," says Sudhakar Rao of
Hitachi Data Systems.
Traditionally, SANs require a separate dedicated infrastru-cture to
interconnect hosts and storage systems. The primary transport protocol for this
interconnection has been. FC networks provide a serial transport for the SCSI
protocol. In addition, IP data transport networks have been built to support the
front end and back end of IP application servers and their associated storage.
"But unlike IP SAN, FC cannot be easily transported over lower bandwidth
long-distance WAN networks in its native form, and therefore, requires special
gateway hardware and protocols. The use of iSCSI over IP networks does not
necessarily replace a FC network but provides a transport for IP-attached hosts
to access fiber channel-based targets," says Sanjay Kharade, principal
consultant, Cisco Systems, India and SAARC.
The major drivers
Economic pressures will force customers to look at alternatives, analysts
say. The price difference between an FC and an IP SAN is fundamentally on three
points: cost of acqui-sition, cost of managing the network and cost of adding
the components. The cost of acqui-sition for FC has been coming down, but is
still double the price of an NIC (Network Interface Card). A gigabit NIC card is
available at $60-70 today. A Fiber HBA (Host BUS Adapter) would not cost less
than $300-400. Intransa expects the IP SAN market to touch about 27 percent of
the global storage market by 2007.
Cisco feels that the industry is positively looking at IP SAN as a solution
and is expecting an increase in adoption in the next one year. What is driving
the IP SAN market is its ability to deliver SAN at a fraction of the cost and
complexity of FC and its superior performance and scalability over NAS.
Initially, very few FC vendors embraced iSCSI, but now they're interested.
"With the global ratification of iSCSI standards, we expect to see a
gradual adoption of IP SANs, particularly with SMB customers who see IP SAN as a
cost-effective alternative," says Kharade.
So vendors are now busy educating prospective buyers, convincing them that IP
network over NAS was a com-promise, and rooting for the power of the IP. But
will it be hot enough? Only 2005 will decide.
Goutam Das