Servers provide various facilities to disk based and diskless clients. These facilities include:
centralized file access
boot image downloading for diskless clients
boot image manipulation tools
remote client management tools
LAN and WAN gateway facilities
These facilities can be grouped into the following functional classes:
administration
application
boot
installation
A single server may provide all of the functionality list
above or just part of it. An additional aspect
is that the servers do not necessarily need to
run SCO OpenServer. The table below shows the basic requirements
for each type of server.
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Server type Operating system BOOTP/TFTP TCP/IP
----------------------------------------------------------
Administration SCO OpenServer only n/a yes
Application Any n/a yes
Boot Any multitasking yes yes
Installation SCO OpenServer only yes yes
NOTE:
If you want to use a non-SCO OpenServer system as a boot
server you will temporarily need an OpenServer
system to act as an intermediate installation server. All
the required product files must first be installed on
the intermediate server using custom. Once installed, an image
of the products and the directory structure in which
they reside can be copied across to the non-SCO OpenServer
system using, for example, ftp.
The level of facilities that can be supported by a
server is highly dependent on the hardware configuration and
the desired level of performance. If a single system
is used to support all four functions, it may
require far more resources than if two systems each
support two of the functions.
As well as providing centralized file access and database
facilities, servers may also provide client management facilities as
part of the standard operating system. In addition, they
can be used as gateways to other LANs and
WANs. The diagram below shows an example of how
a client server configuration may look. It includes an
SCO OpenServer system as an administrative and application server, a
client controller, some diskless clients and a remote mainframe
database server.
Figure 2-4 Example configuration
The high reliability of the SCO OpenServer HTFS™ &
DTFS™ filesystem provides the robustness required by
server systems. Provisions for UPS services give additional
protection by enabling servers to
continue operations even during power outages. Further protection can
be introduced by using disk mirroring on a single
server or by using primary and secondary servers
with mirrored services and data on both.
