SG350X-MP Stacking Ports

[encojosh]

We have 3 SG350X-MP stacked together.  The master switch is connected to the two slaves directly over SFP ports.  There are no connections between the slave ports.

1. Why are two stacking ports required for each switch?  Is there a main and a backup?  If so, can you get by with just one stacking port?  We don't need redundancy in this scenario.
2. Both slaves are randomly disconnecting, one frequently and the other infrequently.  The one disconnecting frequently has the most traffic.  The fiber may be to blame, but I suspect it is the Unifi SFP+ 10G modules.  Would you suggest switching to the SFP-10G-SR SFP+ modules or looking somewhere else?

%Stack-E-STCK-EXCEP-HNDLR: Lost connection with unit 3 reason : connection timeout. Unit will be rebooted . 

[Reza Sharifi]

Why are two stacking ports required for each switch?  Is there a main and a backup?  If so, can you get by with just one stacking port?  We don't need redundancy in this scenario.

Correct, 2 ports are for redundancy and higher bandwidth. If you don't need nether one, you can just use one.

HTH