Troubleshooting guide

64 Advanced System Diagnostics and Troubleshooting Guide
Diagnostics
Limited Operation Mode
A switch enters limited operation mode when some system health check action prevents it from
booting. In limited operation mode, all tasks are suspended, I/O modules are powered down, and a
limited set of commands are available for troubleshooting or corrective action. Both manual and
automatic diagnostics results can put the switch into limited operation mode.
In limited operation mode, only the CPU, NVRAM, management port, console port, a limited set of
system tasks, and a limited subset of CLI commands are active.
Ports are powered down so that links to adjacent devices do not come up. The switch fabric is not
operational. Limited operation mode allows diagnostic work to be done on failed devices while
redundant backup devices continue to operate.
For more information about limited operation mode, see Appendix A, “Limited Operation Mode and
Minimal Operation Mode.”
Effects of Running Memory Scanning on “ i ” Series Switches
The packet memory scan is an invasive diagnostic. The impact of the packet memory scan depends on
the “i” series switch type and—in the case of the BlackDiamond switch—whether the BlackDiamond is
equipped with a single MSM or redundant MSMs.
Summit, Alpine, or BlackDiamond with a Single MSM
Summit, Alpine, and single-MSM BlackDiamond systems are taken down during the time the packet
memory scan is running.
BlackDiamond System with Two MSMs
During the scanning period, the module is taken offline. Expect a minimum offline time of 90 seconds.
Up to eight correctable single-bit errors are corrected, with minimal loss to the total memory buffers.
In extremely rare cases, non-correctable errors are detected by memory scanning. In these
circumstances, the condition is noted, but no corrective action is possible. When operating in the
manual mode of memory scanning, the module is returned to online service after all possible corrective
actions have been taken.
BlackDiamond with one MSM64i
(or slave MSM64i is offline)
Yes
No
Switch enters limited commands mode.
Switch kept online.
BlackDiamond with two MSM64i
modules; errors on master
Yes
No
Master MSM64i fails over.
MSM64i kept online.
BlackDiamond with two MSM64i
modules; errors on slave
Yes
No
MSM64i taken offline.
MSM64i kept online.
BlackDiamond 6816 MSM64i
modules in slots C and D
Yes
No
Module taken offline.
Module kept online.
Alpine and BlackDiamond
“i”-series I/O modules
Yes
No
Module taken offline.
Module kept online.
Table 8: Manual diagnostics memory scanning and memory mapping behavior, extended (continued)
Platform Errors Detected? Behavior