JGroups send and receive buffers warning when clustering is used in JBoss EAP and JDG

Issue

• Warnings show up the log:

  WARNING [org.jgroups.protocols.UDP] (ChannelService lifecycle - 1) send buffer of socket java.net.MulticastSocket@60c42064 was set to 640KB, but the OS only allocated 131.07KB. This might lead to performance problems. Please set your max send buffer in the OS correctly (e.g. net.core.wmem_max on Linux)
  
  WARNING [org.jgroups.protocols.UDP] (ChannelService lifecycle - 1) receive buffer of socket java.net.MulticastSocket@60c42064 was set to 25MB, but the OS only allocated 131.07KB. This might lead to performance problems. Please set your max receive buffer in the OS correctly (e.g. net.core.rmem_max on Linux)
  
  WARN  [org.jgroups.protocols.UDP] (ServerService Thread Pool -- 63) [JGRP00014] the receive buffer of socket ManagedDatagramSocket was set to 20MB, but the OS only allocated 2.1MB. This might lead to performance problems. Please set your max receive buffer in the OS correctly (e.g. net.core.rmem_max on Linux)
  
  WARN  [org.jgroups.protocols.UDP] (ServerService Thread Pool -- 63) JGRP000014: the send buffer of socket MulticastSocket was set to 640KB, but the OS only allocated 131.07KB. This might lead to performance problems. Please set your max send buffer in the OS correctly (e.g. net.core.wmem_max on Linux)
  WARN  [org.jgroups.protocols.UDP] (ServerService Thread Pool -- 63) JGRP000014: the receive buffer of socket MulticastSocket was set to 25MB, but the OS only allocated 131.07KB. This might lead to performance problems. Please set your max receive buffer in the OS correctly (e.g. net.core.rmem_max on Linux)
  

• Is 640KB (send buffer) and 25MB (receive buffer) a minimum recommended requirement for UDP?

• What are good/safe baselines for these values?

• Will hard coding these values effect TCP auto tuning in any fashion?

• Are there any side effects to setting these values that should be considered?

• How does one adjust the send and receive buffers?