Administrator Guide

show redundancy
3 Displays input and output flow statistics on a stacked port.
show hardware stack-unit unit-number stack-port port-number
4 Clears statistics on the specified stack unit. The valid stack-unit numbers are from 0 to 5.
clear hardware stack-unit unit-number counters
5 Displays the current operational mode of the Aggregator (standalone or stacking) and the mode in
which the Aggregator will operate at the next reload.
show system stack-unit unit-number iom-mode
Failure Scenarios
The following sections describe some of the common fault conditions that can happen in a switch stack and
how they are resolved.
Stack Member Fails
• Problem: A unit that is not the stack master fails in an operational stack.
• Resolution: If a stack member fails in a daisy chain topology, a split stack occurs. If a member unit fails
in a ring topology, traffic is re-routed over existing stack links.
The following syslog messages are generated when a member unit fails:
Dell#May 31 01:46:17: %STKUNIT3-M:CP %IPC-2-STATUS: target stack unit 4 not
responding
May 31 01:46:17: %STKUNIT3-M:CP %CHMGR-2-STACKUNIT_DOWN: Major alarm: Stack unit 4
down - IPC
timeout
Dell#May 31 01:46:17: %STKUNIT3-M:CP %IFMGR-1-DEL_PORT: Removed port: Te
4/1-32,41-48, Fo 4/
49,53
Dell#May 31 01:46:18: %STKUNIT5-S:CP %IFMGR-1-DEL_PORT: Removed port: Te
4/1-32,41-48, Fo 4/
49,53
Unplugged Stacking Cable
• Problem: A stacking cable is unplugged from a member switch. The stack loses half of its bandwidth
from the disconnected switch.
• Resolution: Intra-stack traffic is re-routed on another link using the redundant stacking port on the
switch. A recalculation of control plane and data plane connections is performed.
Master Switch Fails
• Problem: The master switch fails due to a hardware fault, software crash, or power loss.
• Resolution: A failover procedure begins:
1 Keep-alive messages from the Aggregator master switch time out after 60 seconds and the switch is
removed from the stack.
Stacking 859