Subject: the lure of the san
network world fusion focus : amy larsen decarlo
on storage in the enterprise
today ' s focus : the lure of the san
03 / 14 / 00
dear wincenty kaminski ,
today ' s focus : the lure of the san
by amy larsen decarlo
e - business is changing how businesses value information . information
has become a strategic asset that gives companies an edge over their
market rivals . companies use intelligence to identify new markets and
make contact with prospective customers . in this media - saturated era ,
information itself is packaged and sold as a product . this makes the
ability to supply users with fast access to stored information on a
continuous basis absolutely crucial .
companies are clearly coming to a crossroads in their storage
implementations . with estimates for internet storage capacity needs
doubling every three months , it professionals are hungry for a scalable
solution to help them consolidate control of stored information . they
often look to storage - area networks ( san ) as a better option to manage
their information storage systems than distributed models .
today , most organizations rely on a distributed storage model that uses
file servers to process i / o requests from end users and other
application servers . in this model , all requests for data go through
the file server that owns the attached storage disks , and only one file
server can tap data on a particular disk via a scsi bus .
this model has several shortcomings . first , the amount of data a
server can access is restricted to the number of disks supported by the
bus , which limits the capacity of a single file server . second , because
the server processes each i / o request , it risks becoming a bottleneck .
third , this server model carries some daunting availability limitations ,
because only one file server is allowed to access a set of disks . if
that file server or any of its scsi connections fails , then users and
other application servers lose access to the stored files .
this model carries other major disadvantages . distributed file servers
rely on the data transport network to run backup and recovery operations
which can eat up bandwidth and slow normal network transmissions to a
crawl . finally , this decentralized setup is difficult to manage from
both a logical and a physical perspective . file server based storage
systems are distributed throughout the enterprise , so it is often
difficult to assess current and future capacity needs . and because
these servers use a parallel cabling scheme to link the file server to
the disk array , they can also be cumbersome to set up and manage .
sans promise to mitigate the problems that plague conventional file
servers , largely through consolidation of control . these specialized
storage networks claim higher availability , faster performance ,
centralized management , and by their architecture , the capability to
remove bandwidth - intensive data backup and recovery operations from the
lan . this frees up the lan for normal data communications and ensures
smoother back - up operations .
using high - speed transports like fibre channel , sans offer a high -
performance network optimized for moving storage data . sans also make
way for new storage implementations like lan - free backup . and , because
fibre channel can support distances of up to 10 kilometers , san devices
can be widely distributed , but also centrally managed as one network .
yet , as was the case with lans in their younger years , sans are still
developing . vendors are still working out major product interoperability
issues , while companies deploying san technology struggle with how to
merge the very different worlds of storage and networks and manage both
together . ultimately the hope is that , like lans , sans will develop into
a mature and highly manageable solution that supplies substantial
benefits at lower costs .
given that storage deployment and ongoing support costs can total 10
times the acquisition price for the equipment , the consolidated
management capabilities of a san may deliver the biggest benefit to
business .
to contact amy larsen decarlo :
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
amy larsen decarlo is an analyst with enterprise management associates
in boulder , colo . , ( http : / / www . . com ) , a leading
analyst and market research firm focusing exclusively on all aspects of
enterprise management . she focuses on storage management , application
management , and security . in her position , she oversees market research
and contributes to custom project work in her focal coverage areas .
prior to joining ema , amy spent five years covering enterprise
management for industry trade magazines , including informationweek and
data communications . she can be reached at
mailto : decarlo @ . com
for related links - - click here for network world ' s home page :
http : / / www . nwfusion . com
storage networking industry association ( snia ) :
http : / / www . snia . org
fibre channel industry association ( fcia ) :
http : / / www . fibrechannel . com
scsi trade association ( sta )
http : / / www . scsita . org
other storage - related articles from network world :
legato primes storage resource mgmt , network world , 03 / 13 / 00
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