Unable to change MTU size of my core switch

[nomansafdar]

i have cisco switch C3560E Version 12.2(55)SE6, it showing me the mtu on each interface is 9000. when i try to change it globally by using "system mtu 1500" nothing happens. please suggest whats the reason of this mtu size.

[balaji.bandi]

check below guide :

https://www.cisco.com/c/en/us/support/docs/switches/catalyst-6000-series-switches/24048-148.html#c3

If you do not have devices which required MTU 9000, there is no need to enable.

[nomansafdar]

please guide which command to keep and which to remove?

Core-Switch-B#sh system mtu

System MTU size is 1500 bytes
System Jumbo MTU size is 9000 bytes
System Alternate MTU size is 1500 bytes
Routing MTU size is 1500 bytes

[balaji.bandi]

If you do not need Jumbo frames, i will keep standard MTU 1500

[nomansafdar]

i have changed the command to "system mtu jumbo 1500" but i want to completely remove this command and want to keep standard mtu 1500?

[balaji.bandi]

if you configure system mtu 1500, that is global config should work.

show system mtu (show you what is effective config)

[nomansafdar]

Core-Switch-B#sh system mtu

System MTU size is 1500 bytes
System Jumbo MTU size is 1500 bytes
System Alternate MTU size is 1500 bytes
Routing MTU size is 1500 bytes

this is what i see 

[balaji.bandi]

all good here as per i see the output.  (we are in agreement you do not need jumbo frame )

[MHM Cisco World]

Interface mtu overrides the global sw mtu.

must change or default mtu under interface then change it in global