Specifications

Site Planning for Fault-Tolerant Systems
Site Planning for ftServer V 2302, V 4304, and V 6308 Systems 1-3
Site Planning for Fault-Tolerant Systems
Consider the following specific fault-tolerant features of ftServer systems for site
planning:
• Lockstep technology means that the systems contain redundant hardware. The
systems contain two enclosures, each containing a full computing environment that
consists of a CPU element and an I/O element.
If a component in a CPU element malfunctions, the corresponding CPU element in
the other enclosure, which is processing the same information in lockstep,
continues processing without interruption. If a component in the I/O element
malfunctions, the system fails operation over to the corresponding element in the
other enclosure and continues to operate normally. The only consequences are
that the system is less fault tolerant, and any I/O throughput distributed between
the enclosures may be reduced. To restore full fault tolerance, an enclosure can be
replaced without taking the system offline.
• ftServer systems can connect to the Remote Service Network (RSN).
Connecting a system to the RSN allows the CAC or your authorized Stratus service
representative to remotely diagnose, troubleshoot, and resolve problems online.
An RSN modem and console server, managed by system software, connect to the
system to enable connectivity to the RSN.
Site Planning Checklist
Referring to the information in this document, answer the following questions:
Planning for RSN Connectivity
❏ Will your system connect to the RSN? If so, will it connect over an RSN modem
❏ Do you have an external analog telephone line available for the RSN modem?
NOTE
A dedicated phone line provides the most reliable service.
RSN calls routed through a PBX may be slow due to load
on the PBX, or may not complete successfully due to
disconnections. If you must use a PBX, do not route the
telephone extension through a switchboard; instead,
provide a direct-dial analog number.
❏ Do you have an additional telephone connection and telephone near the operator’s
station for voice communications when calling for support?