Will enabling flow controll on Cisco switch port disrupt current connections?

No test/spare equipment you can test this on? Its the safest way!

It doesnt seem to be a feature that would require the interface to bounce but under high traffic loads i wouldnt be surprised if some packets were dropped. So there is an element of risk so in summary what i'm saying is i wouldnt do it if i were in your shoes try securing downtime from the business. Redundant network connections between devices play a role here if you have them in place.

I do have redundant connections. This is on my iSCSI SAN network. All devices have multiple connections. Some how not all ports on the switches have flow control enabled. I think I'll do it off hours though. But you are thinking that enabling will not cause a port to reset or anything, just that since the config is changing there is a chance of a few dropped packets?

Yeah there is a potential risk if you consider a highly utilized link and enabling flow control on link, there could be a point were one side is sending pause frame while the other side does not respond to them which may or may not result to some packets being lost.

Thanks to all.