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By Henry Baltazar, eWEEK,
August 13, 2002
The release of the iSCSI
specification is just around the corner, and, based on eWeek Labs'
tests of iSCSI-based products and analysis of the evolving
specification, iSCSI will offer organizations an inexpensive,
effective means to a SAN end.
iSCSI is an IP-based
protocol that enables the block-level transfer of data over a
network. From a server's perspective, iSCSI essentially allows
standard Fast Ethernet and Gigabit Ethernet network cards to
function like storage area network controllers. iSCSI will also
allow shared storage solutions such as tape drives and RAID units to
be shared over IP.
Although the iSCSI
specification is still in development, products that take advantage
of this new storage protocol are already on the market. In fact,
they have been kicking around in testing labs and early-adopter
sites for close to a year now.
The most compelling use
for iSCSI is for SAN expansion to low-end and midrange servers.
Using storage routers such as Cisco Systems Inc.'s Cisco SN 5428, IT
managers will be able to hook more servers into their storage
networks and take advantage of the IP networks they already have in
place. This will save organizations tens of thousands of dollars
over Fibre Channel HBAs (host bus adapters), which typically cost
from $1,000 to $1,500 each.
In addition, because
iSCSI runs on standard IP networks, there is no need to implement
Fibre Channel switches throughout a corporation. IT administrators
can instead make use of Gigabit Ethernet network adapters, which
cost a fraction of the price of Fibre Channel HBAs and are now built
into many new servers' motherboards.
iSCSI also cuts costs in
less tangible ways. The number of people skilled in IP networking is
still far higher than those with Fibre Channel networking expertise,
and it is unlikely that an influx of Fibre Channel know-how will
flood the market any time soon. Organizations can thus tap the
expertise that already exists in-house.
Manageability is another
area where iSCSI can cut costs. While security and QOS
(quality-of-service) technologies are almost foreign concepts in the
Fibre Channel world, they already exist in the IP world and might
improve the manageability of SANs using iSCSI. Indeed, based on what
we have seen from the Internet Engineering Task Force IP storage
group, the iSCSI management standards are nearly complete and so
will be available to organizations making the move to iSCSI.
iSCSI will also serve as
a capable means for enabling long-range data mirroring for disaster
recovery, allowing servers in one data center to back up data to
remote tape drives. With the abundance of IP networks available, IT
managers will be able to use virtual private networks to create
secure tunnels between sites to transfer data over the Internet,
providing an economical alternative to running leased lines from
site to site.
Performance
Concerns >>
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