Enable jumbo frames on cisco asa

multicontext mode

per context

changeto context foo

mtu inside 9200
mtu outside 9200

You get the message:

INFO: Jumbo frames should be enabled to receive packets more than 1500 MTU
      Use 'jumbo-frame reservation' command to turn on jumbo frame

INFO: TCP MSS may need to be adjusted using 'sysopt connections tcpmss'
      command to pass large TCP segments

changeto context system

jumbo-frame reservation

You get the message:

WARNING: This command will take effect after the running-config is saved and the system has been rebooted. Command accepted.

WARNING: Failover Detected - Please remember to reboot both devices in the failover set. This can be done with zero downtime by rebooting one at a time.

INFO: Interface MTU should be increased to avoid fragmenting
      jumbo frames during transmit

write mem all
...
no failover active
...
reload
...
failover active
...
failover exec mate reload noconfirm