EAP 7.2 Configuration Guide - Chapter 17.3. Configuring Byte Buffer Pools only mentions how to create, update and delete Undertow's Byte Buffer Pool. However, just adding byte-buffer-pool does not become effective on the listener. To enable the created byte-buffer-pool needs to specify the buffer-pool attribute on each listener (http-listener, ajp-listener, https-listener).

• For http-listener:

  /subsystem=undertow/server=default-server/http-listener=default:write-attribute(name=buffer-pool,value=newByteBufferPool)
  

• For ajp-listener:

  /subsystem=undertow/server=default-server/ajp-listener=ajp:write-attribute(name=buffer-pool,value=newByteBufferPool)
  

• For https-listener:

  /subsystem=undertow/server=default-server/https-listener=https:write-attribute(name=buffer-pool,value=newByteBufferPool)