Interesting remarks by potental FC SAN customers, in a post to the Compaq thread:
To: +hlpinout (46408 )
From: +hlpinout
Saturday, May 22 1999 6:50AM ET
Reply # of 61942
In Focus: Storage Area Networking -- Users Demand
Interoperable Products May. 21, 1999 (InternetWeek - CMP
via COMTEX) -- There's a huge disconnect between
the hype and reality surrounding storage area networks.
The hype: Every server on a network-regardless of
operating system, architecture and manufacturer-can tap
into an unlimited pool of storage devices interconnected
on a separate Fibre Channel network, which may be
located thousands of miles away. SANs are also more
reliable, the theory goes, because storage
components and servers become swappable parts, easily
replaced if a server goes down. Likewise, if storage goes down,
a hot backup is waiting to pick up the load.
The reality: SANs have only limited interoperability among
vendors' products and can span distances of only a few miles.
Data sharing is compromised by incompatible file systems and
data formats across disparate operating systems. Management tools
that configure and back up heterogeneous SANs are sorely lacking.
Because of these limitations, a single SAN can't do the job
for a supercomputing center that serves the U.S.Department of Defense. Instead, the center, which is on Wright-Patterson Air Force Base, has three SANs-one attached to a bank of IBM SP RS/6000 servers, the second to Sun Microsystems E10000 servers and the third to Silicon Graphics Origin 2000 servers. The three SANs comprise storage devices from Data General, IBM, MetaStor, StorageTek and Sun.
But having separate, architecture-specific SANs isn't the ideal
configuration because "we have to have interoperability," said Wade
McLean, integration director for Nichols Research Corp., the prime
integrator that runs the center.The industry is moving forward, however.
For example, the Storage Networking Industry Association (SNIA),
a consortium of about 50 makers of disk and tape systems, Fibre Channel
switches and management software, last week passed a series of measures
designed to promote interoperability of multiple vendors' devices. That work
includes developing a business plan for setting up an interoperability lab
for SAN gear and recruiting a panel of IT managers to guide the standards
process.
The association is also developing a set of standard management
formats, Management Information Bases (MIBs), for configuring storage
devices and for reporting their status and capacity. Those standards are
expected to become widespread next year, said Clodoaldo Barrera,
director of storage systems strategy for IBM.
The SNIA has already completed work on a standard interface to allow
devices from different vendors to interoperate on backup, with one vendor's
device taking backup data from another's. That standard, called Third-Party Copy,
is being reviewed by ANSI for final approval. Indeed, vendors have a stake in
cooperating in building interoperable SANs. Unlike other, splintered vendor
movements, which pitted thin clients vs. conventional desktop PCs, and set
Java against conventional operating systems, the vendor vision behind
SANs is universal-and it's driven by customer demand.
"The others were technologies looking for implementations," said
Dwight Gibbs, chief technologist for the Motley Fool online financial advisory.
"Vendors said, 'We have this technology-what are we going to do with it?' This is
a need looking for the right technology. Anyone can see where the utility is. Fast
as SCSI is, it ain't Fibre Channel."
The Motley Fool has developed two separate SANs to simplify backup and
data management. One SAN consists of Network Appliance file servers that serve
up Web pages, and the other is an 80-GB Compaq disk array connected to four
Compaq ProLiant file servers.
"SANs are not something we came up with and had to talk customers into," said Darren
Thomas, vice president of the multivendor storage business unit at Compaq.
Despite the current disconnect between hype and reality, a survey by Strategic Research
reveals that enterprises are putting their money into SANs, with a predicted
tenfold increase in spending on SANs from 1998 to 2003.
Demand for SANs is driven in part by the un-predictability of traffic on commerce Web
sites, requiring e-businesses to set up flexible, reliable and fast access to data.
Enterprise resource planning and decision-support applications are also driving SANs
because of the large data volumes they generate. And all Internet applications need to be
available continuously because of the round-the-clock nature of the global economy.
But because of the large technical barriers to adoption, SANs are still one to two years away
from becoming mainstream, said Kris Newton, an analyst at Strategic Research Corp.
Mostly, what's needed are multivendor standards for hardware and software
interoperability, and that's a tricky pro-cess, she said.
Aside from interoperating, SAN products also must get more robust. For instance,
Fibre Channel switches, the networking backbone for SANs, are still unreliable,
customers say.
"It's like the first generation of anything: There are bugs to be worked out," said Ken
Mangold, director of network services for J.B. Hunt Transport Services, which is
evaluating SANs for data warehousing and hopes to have a pilot running by the third quarter.
File sharing is also a complex problem, acknowledged Compaq's Thomas. Compaq is
developing a product, scheduled to come out by early 2001, that will maintain file
formats separately from data servers so that applications can read files anywhere on the
network, independent of server platform or operating system.
"Heterogeneity is a promise I have yet to see lived out," said Dirk Van Dall, a principal
consultant for digital video at Showtime Networks. Showtime uses a 1-terabyte SAN
connected to a network of Apple Macintosh computers to compile video for cable TV.
Van Dall would also like to mix in Windows NT systems but has found that technically
impossible.
Happy In Homogeneity
In cases where heterogeneity isn't an issue, then SANs are considered a lifesaver.
"We are getting good performance from our disk subsystem, and we are positioning
ourselves for more advanced clustering in the future," said Joe Patterson, senior network
engineer for Tutor Time Learning Systems Inc., a chain of about 200 child-care centers
throughout the country. "We're completely a Microsoft shop here, so the ability to mix
servers is not so important for us."
Tutor Time's pure-IBM/Microsoft SAN supports a database application running on
about 10 IBM Netfinity and IBM PC 325 servers. The PC servers run Microsoft Windows
NT, SQL Server and Cluster Server. To Hewlett-Packard, support for just two brands of
storage devices-its own and EMC's-is sufficient for satisfying its customer needs. On
the server, HP supports HP/UX, Sun Solaris and Windows NT, and it will add
IBM AIX support in July.
Customers want to have only two vendors, to permit competitive bidding, rather
than a large array of systems that require separate support, said David Scott, worldwide
marketing director for HP's enterprise storage unit.
Extending The Boundaries
Another area of functionality where SANs have fallen short is distance. Vendors speak of
globally distributed networks, where a server in New York can tap into a SAN in
Florida-either because that's the nearest available storage or because there is no local storage.
At this time, Fibre Channel stretches about 30 miles with extenders, which is only good
inside a single municipality. Compaq sometime this year expects to introduce hardware
designed to allow storage to connect over ATM and standard tele-phone lines.
Fixing the software to support widely distributed SANs is a tougher problem. Today's
operating systems and applications don't tolerate significant latency in accessing
storage and will assume a storage device is down if it fails to respond immediately,
though it may simply be failing to respond because of distance delays or network
latency. Compaq's software, as well as that from other vendors, will be revised by
next year, Thomas said.
SAN management is also lacking. Vendors such as Computer Associates International Inc.
and Tivoli Systems are beginning to integrate storage controls into their
enterprise-management platforms to give IT managers a single view of their entire systems.
Needed features include the ability to resize and reconfigure disk volumes on the fly and
built-in security to ensure that servers don't read or write data for which they are not
authorized.
In the meantime, because standard management software packages from CA and
Tivoli have proved inadequate, the Defense Department's supercomputing center has
developed its own management tools for the lab's hardware hodgepodge. But still
lacking is the ability to create and manage file systems that can be read and written
by multiple vendors' storage hardware and multiple vendors' operating system,
McLean said.
Vendors and users alike see today's hype blurring into reality over time.
"I think SANs will succeed," said Strategic Research's Newton. "It's necessary. End
user and IT demand will drive things."
---
SAN Boxes: Major vendors sell ready-made SANs, including rack-mounted disk arrays
with SAN firmware and Fibre Channel connectivity.
Compaq-StorageWorks Enterprise Storage Array connects to heterogeneous
Windows NT and Novell NetWare networks, or homogeneous NetWare, NT, Tru64 Unix,
Sun Solaris, HP-UX, IBM AIX, SGI IRIX, SCO Unix or OpenVMS networks
EMC-Symmetrix Enterprise Storage SAN supports servers running
Unix, NT, AS/400, NetWare and mainframes
Hewlett-Packard-SureStore E supports HP-UX, Solaris, NT; in July,
support for IBM AIX will be added
IBM-7133 Advanced Serial Disk System connects to Unix and NT
servers, and will support NetWare at a future unannounced time
Sun-StorEdge A5000 supports Solaris and NT servers
---
SAN Shortcomings
-Heterogeneity: Support is limited for storage devices and servers from multiple vendors
-Distance: Storage must be located within a few miles of servers
-Manageability: Products can't be integrated into a single management
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