Administrator Guide

The master synchronizes the following information with the standby unit:
• Stack unit topology
• Stack running configuration (which includes ACL, LACP, STP, SPAN, and so on.)
• Logs.
The master switch maintains stack operation with minimal impact in the event of:
• Switch failure
• Inter-switch stacking link failure
• Switch insertion
• Switch removal
If the master switch goes off line, the standby replaces it as the new master and the switch with the next highest priority or MAC address
becomes standby.
Stack Master Election
The stack elects a master and standby unit at bootup time based on two criteria.
• Unit priority — User-configurable. The range is from 1 to 14. A higher value (14) means a higher priority. The default is 0. By
removing the stack-unit priority using the
no stack-unit priority command, you can set the priority back to the default value
of zero. The unit with the highest priority is elected the master management unit; the unit with the second highest priority is elected
the standby unit.
• MAC address (in case of priority tie) — The unit with the higher MAC value becomes the master unit. The stack takes the MAC
address of the master unit and retains it unless it is reloaded.
To view which switch is the stack master, enter the show system command.
DellEMC#show system
Stack MAC : 34:17:17:18:19:1e
Reload-Type : normal-reload [Next boot : normal-reload]
-- Unit 1 --
Unit Type : Member Unit
Status : online
Next Boot : online
Required Type : S3124F - 28-port GE/TE (S3100)
Current Type : S3124F - 28-port GE/TE (S3100)
Master priority : 0
Hardware Rev : 5.0
Num Ports : 30
Up Time : 43 min, 41 sec
Dell Networking OS Version : 1-0(0-4679)
Jumbo Capable : yes
POE Capable : no
FIPS Mode : disabled
Burned In MAC : f8:10:20:30:40:97
No Of MACs : 3
-- Module 1 --
Status : not present
-- Power Supplies --
Unit Bay Status Type FanStatus FanSpeed(rpm)
---------------------------------------------------------------------------
1 1 up UNKNOWN up 0
1 2 absent absent 0
-- Fan Status --
Unit Bay TrayStatus Fan1 Speed Fan2 Speed
------------------------------------------------------------------------------------
1 1 up up 7058 up 7164
Speed in RPM
-- Unit 2 --
Unit Type : Member Unit
Status : online
Next Boot : online
794
Stacking