Thin servers cut fat from LAN menus

Is your server feeling bloated these days?

Client-server computing was supposed to rescue us from centralized mainframe networks
by distributing the information more evenly. Instead, as enterprise data grew, the servers
have gotten fatter and more expensive to manage.

The recent trend toward a distributed server model has a new twist. In addition to
setting up server-class hardware, loading an operating system and establishing thin-client
accounts, you now can attach extra devices called thin servers to meet different kinds of
storage needs.

Some vendors refer to thin servers as network appliances or modules that plug into a
network similar to the way users plug peripherals into PCs.

Network OSes such as Microsoft Windows NT Server, Novell IntranetWare 4.11 and Unix all
carry considerable overhead. Thin-server devices are different.

They act like conventional servers but have no real OS interface. Instead, they perform
server operations through a combination of hard-wired instructions and limited software or
firmware.

Thin servers provide access to CD-ROM, tape and other backup media. But products are
already available that can take over file-server functions on an NT operating system.

The GCN Lab will give you an overview of thin servers. The lab also reviewed two
thin-server products: the Millenia Series 700 CD tower from SMS Data Products Group Inc. (see
story, next page) and the Axis StorPoint HD/4 for Jaz from Axis Communications Inc. (see
story below).

Network devices started their evolution when multiple users began sharing a few
printers across a LAN. Scanners, modem pools and fax devices soon followed. All are
relatively low or intermittent users of bandwidth and usually act as clients on a network.

Thin servers take that model and beef it up for high-bandwidth data availability.

Many people refer to servers running Microsoft and Novell OSes as file servers, but
that is a misnomer. File servers can simultaneously function as Web or application
servers. But even if you do not impose Web or application server duties, the pure file
server functions will suffer from any extra overhead on the network.

One great advantage of thin servers is that they focus totally on file service,
improving performance in that one area.

A second advantage is low maintenance. Just as boat owners complain that a boat is a
hole in the water into which they pour money, network managers begrudge their servers'
maintenance costs.

Constant demands for more memory, more storage and more OS upgrades suck up financial
resources and administrators' energy. Every time you change a server configuration, you
increase the chances of instability and catastrophic failure.

Even when an upgrade goes well, the system complexity and the risk of component
conflicts will rise. The less complex a system, the easier it is to maintain.

High availability is important, too. Modular design permits easy replacement of failed
components and is standard for high-availability servers, but it's far easier to do in
thin servers, thanks to their lower complexity.

Another advantage is easier management. Thin servers can have several interfaces for
configuration and management; the most common is a direct null-modem serial connection for
PCs.

With this connection and a Telnet program, you can configure a thin server from the
command line prompt. Depending on the type of network and device, you could configure with
just a network connection and Telnet. But such interfaces are clumsy and inefficient for
common tasks.

This is where proprietary programs and Web interfaces take over. Web interfaces
obviously are preferable, giving administrators the greatest flexibility in terms of
management platforms.

Many thin servers support both TCP/IP and Hypertext Transfer Protocol, so they are a
good choice for Web service on intranets or the Internet. For example, you could store on
CD-ROM all the pages and data that make up a Web site.

When the CD-ROMs are served up by a Web-enabled thin server, the site will be
impervious to hacking, because the media cannot be changed or overwritten.

Some companies sell thin servers specially configured as Web servers with hard drives
and CD-ROM drives for publishing to the Internet. Thin Web servers not only support static
sites, they can also handle Microsoft Corp.'s Active Server Pages and FrontPage, as well
as tools from Netscape Communications Corp. Thin-server support for JavaScript, Visual
Basic Script and Perl is available, too.

What's the downside? Most thin-server storage products are limited to 10Base-T
networks, although 100Base-T products are available. But many cannot support high levels
of bandwidth or throughput.

There's another fault in some thin servers: lack of modularity. If a piece of hardware
breaks or some software component can no longer be upgraded, you are stuck with an
expensive doorstop.

Thin servers always run a bare-bones OS, which may be unsuitable for government
environments that demand security, fault tolerance and interoperability.

But not all the devices suffer from those lacks. We can expect thin servers to deliver
higher throughput than general-purpose servers in coming years, plus better functionality
in other areas.

All in all, modular networks that mix general-purpose, thin and high-end application
servers should extend the capabilities on tomorrow's enterprise environments. So think
about cutting some of the fat on your network.