L2 switched frames that exceed the MTU configured on the switch are dropped since fragmentation is a function of L3 routing. Port will not accept the bigger frames and it can not tell the server to do the fragmentation .
MTU command on the SVI affects the MTU size of all packets including IP. IP MTU only affects the MTU of IP packets.
On platforms where the 'system mtu routing' is available, it only applies to L3 interfaces. L3 routed frames that need to be fragmented are software switched and most switches today forward traffic at line rate so it would be bad design if L3 traffic gets fragmented on the switch.
'system mtu' affects the MTU of all the interfaces on the switch.Its a global command and impacts the over all traffic on all the interfaces . Based on the device models , the platform can support jumbo MTU like upto 9000 , which is required for some none standard traffic like FCoE and devices which can generate bigger frames for bulk of data transfer .
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