Specifications

5-6 Sun StorEdge A1000 and A3x00/A3500FC Best Practices Guide • November 2002
There is a Local/Remote switch located on the front panel of each power sequencer.
When the Local/Remote switch is set to Local the sequenced outputs are controlled
by a circuit breaker located on the front panel of each power sequencer. When the
Local/Remote switch is set to Remote, the sequenced outputs are controlled by the
key switch located at the bottom front of the Expansion rack. When the
Local/Remote switch is set to OFF, power is removed from the sequenced outputs.
The unsequenced output is not affected by the position of the Local/Remote switch.
As long as the AC power cord is connected and AC power is available, the
unsequenced output is available.
One possible failure is that only one of the sequenced groups turns on. In this case
you will see only one power supply functioning in some of the disk trays installed in
the Expansion rack. Refer to Chapter 3 in the Sun StorEdge A3500/A3500FC Hardware
Configuration Guide and verify that each disk tray is properly configured.
In a 3x15 configuration, the power sequencers in each rack need to be daisy chained
front to front and back to back (See Section 3.5.2 “Connections Between Power
Sequencers” in the Sun StorEdge A3500/A3500FC Hardware Configuration Guide). The
Local/Remote switch on each power sequencer should be set to Remote. The 2x7 rack
has a front key switch that controls both racks. The 1x8 rack does not have a front
key switch.
5.1.4 SCSI Cables
The most common problem involving SCSI cables is with bent pins on the
connectors. This usually occurs during a system installation. A typical indication of
a defective SCSI cable is an error message indicating SCSI parity errors and the SCSI
transfer rate has been reduced or has switched from wide to narrow SCSI. A SCSI
cable that has failed on the host side usually results in a data path failure indication.
If the problem is with a failed SCSI cable on the drive side, the result is usually in
the form of a drive side channel failure indication. Currently there are no procedures
for testing a SCSI cable for failure other than to replace it with a new or known good
cable. Also, ensure that the SCSI bus length is within the recommended maximum of
25 M (see Section 2.1.5, “SCSI and Fiber-Optic Cables” on page 2-3).