'Copy running-configuration startup-configuration' takes minutes??

I've done this billions of times on Cisco switches, and "copy run start" takes seconds.  When I tried it on my 6248 switch, I get, "This operation may take a few minutes.  Management interfaces will not be available during this time.  Do you want to save  (y/n)

I'm connected to  the switch via SSH -- if I follow through with this config, will it really kill my SSH session, and lock me out of SSH for 2-3 minutes??.    I have 5 VLANs active in the config, and about 20 of the 48 ports are active.  I have a single   4-port  LAG  interface to another switch.   No spanning-tree is configured or needed; everything is in portfast mode.

Thanks!