If switches are stacked together using StackWise, what happens if one of the switches goes down? Is switch stacking bad for redundancy?
Switch Stacking and Redundancy
redundancystackingstackwiseswitch
redundancystackingstackwiseswitch
If switches are stacked together using StackWise, what happens if one of the switches goes down? Is switch stacking bad for redundancy?
Best Answer
In theory, a hardware failure on one member of a switch stack will only cause the physical interfaces of that member switch to go down. Uplinks and access ports on other switches will remain online. The “failover” may be faster than a redundant spanning-tree failover. The single spanning tree instance can also prevent outages, particularly in desktop networks where people are plugging in desktop switches.
I encountered two types of problems with redundant switch stacks in production (although most of this was with the VSS cat6k feature, or with Juniper SRX firewall clusters).
So switch stacks improve redundancy for some types of failures, but increase complexity and impair redundancy for other situations (most notably upgrades).
I personally found switch stacks very helpful in desktop networks (where obtaining a scheduled outage for an impacting upgrade after-hours was not a problem). In the datacenter, where obtaining impacting change windows was almost impossible, I avoided using switch stacks (at least if a server had redundant Ethernet nics, have the two interfaces go to fully independent switches).