ServerNet Cluster 6780 Planning and Installation Guide (G06.24+, H06.03+)

Using the Long-Distance Option

ServerNet Cluster 6780 Planning and Installation Guide—527301-004

G-4

Bandwidth Considerations

With the long-distance option, overall bandwidth is reduced due to end-to-end

transmission latency and lower link transmission rates. Depending on your application

profile, this limit might affect cluster performance.

Although each 6780 switch can support up to eight nodes, you should consider the

number of processors supported by each long-distance link between the switches. To

ensure adequate throughput, under conditions of heavy traffic, each link should

support no more than 12 processors. Using all four links between the switches, this

guideline equates to no more than 48 processors for each 6780 switch, regardless of

the number of nodes.

If one of the four links goes down, the other links must handle the traffic for both the

down link and themselves (an additional 12 processors worth of traffic). An OSM alarm

and EMS events are generated when the link is down. If the bad link remains down, it

must be repaired to regain the lost bandwidth.

Installation Considerations

In general, you can follow the planning, preparation, and installation procedures

described in the main part of this manual to set up a long-distance configuration.

This subsection describes areas where the long-distance installation differs from the

general procedures. Also, throughout the manual, notes have been provided when you

need to be aware of long-distance issues.

Software Installation

For guidance in installing the software, refer to Installing the Server Software on

page 4-4. However, be sure you install the software listed in Table G-1 on page G-3.

To load the firmware and configuration images to the 6780 switches, refer to

Appendix F, Updating the 6780 Switch Logic Board Firmware, Configuration, and

FPGA Images. Be sure to load the versions listed in Table G-1 on page G-3.

Hardware Installation

To install the 6780 switches, follow the procedures in Section 5, Installing 6780

Switches but note the different requirements for the numeric selector settings and

zone-to-zone connections.