White Papers

Merge Two Stacks
You may merge two stacks while they are powered and online.
To merge two stacks, connect one stack to the other using user port cables from the front end user portusing the mini-SAS
cables from the stacking ports.
● Dell EMC Networking OS selects a master stack manager from the two existing managers based on the priority of the stack.
● Dell EMC Networking OS resets all the units in the losing stack; they all become stack members.
● If there is no unit numbering conflict, the stack members retain their previous unit numbers. Otherwise, the stack manager
assigns new unit numbers, based on the order that they come online.
● The stack manager overwrites the startup and running config on the losing stack members with its own to synchronize the
configuration on the new stack members.
Split a Stack
To split a stack, unplug the desired stacking cables.
You may do this at any time, whether the stack is powered or unpowered, and the units are online or offline. Each portion of the
split stack retains the startup and running configuration of the original stack.
For a parent stack that is split into two child stacks, A and B, each with multiple units:
● If one of the new stacks receives the master and the standby management units, it is unaffected by the split.
● If one of the new stacks receives only the master unit, that unit remains the stack manager, and Dell EMC Networking OS
elects a new standby management unit.
● If one of the new stacks receives only the standby unit, it becomes the master unit of the new stack, and Dell EMC
Networking OS elects a new standby unit.
● If one of the new stacks receives neither the master nor the standby management unit, the stack is reset so that a new
election can take place.
Stack Unit and Stack Group Numbering
Enable ports for stacking by specifying a stack-unit number and stack-group number (the stack-unit number stack-
group number command).
● Stack-unit numbers: By default, each switch in Standalone mode is numbered stack-unit 0. Stack-unit numbers are
assigned to member switches when a stack comes up. To pre-configure the units which are the master and standby when
the stack boots up, you can assign unit numbers using the stack-unit renumber command.
● Stack-group numbers: Stacking ports are divided into 16 stack-groups (from 0 to 15), as shown in the following illustration.
Each set of four 10 GbE ports on an Ethernet module or each fixed 40 GbE port on the front panel correspond to a stack
group. Each stack group has 40 GbE of bandwidth.
Usage Notes:
● Stacking is not supported on Fibre Channel ports.
● If you use a Fibre Channel module in an S5000 switch, stacking is not supported on Ethernet ports.
● If you use three or more S5000 units in a stack, you can connect up to a maximum of eight 10 GbE ports or two 40 GbE
ports in links between peer switches.
● If you use only two S5000 units in a stack, you can connect up to four 40 GbE ports in links between the two switches.
Stack groups 0 through 11 consist of four 10 GbE ports; stack groups from 12 to 15 consist of one 40G port as follows:
Stack Group
Ports
0 0 to 3
1 4 to 7
2 8 to 11
3 12 to 15
4 16 to 19
5 20 to 23
6 24 to 27
Stacking 835