Last night I switched my 2748 & 2724 from un-managed to managed. The 2748 went smoothly. The 2724 did not. I did this after hours & did not notice any interruptions with the 2748. But I didn't verify if I had connectivity during the changeover. The following is my experience.  2748 : I used a paper clip to push the manage/un-manage button. I waited for the manage LED to stop flashing. I configured my  laptop with IP 192.168.2.3 & plugged it into a spare port on the switch. I brought up a browser & entered 192.168.2.1 to access the switch web interface. Default log-in is username: admin with blank password. You must click OK. I then changed the IP to our network 10.X.X.X & clicked Apply Changes. I also changed the password. I reset my laptop IP to 10.X.X.X & was able to log-in to the switch. This took a few minutes & I didn't notice any disruptions. 2724: I repeated the above but when I tried to Log-in after changing the IP & password. Apparently this is not uncommon. (see below for the error & link) The switch stopped passing traffic. I tried resetting the switch to un-managed mode by pressing the button. This didn't work. I finally relocated all active cables to open ports on my 2748 & put all unactive cables on a slower backup switch.  I was able to get the switch to reset by holding the button for 30-sec. & waited for the manage LED to stop flashing. I repeated this till I had cycled through managed, un-managed, and back to managed. (I just did this because it just seemed right, not that I had any indication that I needed to)  I rebooted my laptop & cleared all browser history & cache. I log-in to 192.168.2.1. to access the switch web interface. Default log-in is username: admin with blank password. You must click OK. I then changed the IP to our network 10.X.X.X & clicked Apply Changes. I also changed the password. I reset my laptop IP to 10.X.X.X & was able to log-in to the switch. I put the switch back online. ''ERROR User name or password missing'' [URL]  
I have a 2724 in unmanaged mode. I want to know how much traffic is going to/from the different IP addresses. 1) If I change to managed mode, will the 2724 provide the information of how many bytes went to/from different IP addresses over some time period? 2) If yes, then when I switch to managed mode, will it continue to route as it does now, or do I need to manually configure each port? I have a bunch of live sites working fine through the switch, but if I restart the switch in managed mode will those sites all be dead until I do some tedious configuring?
Changing 2724 to managed mode