Hi!
When I'm launching ElasticSearch I get logs like this:
[13:48:24,418][WARN ][jgroups.UDP ] send buffer of socket
java.net.DatagramSocket@46b29c9d was set to 640KB, but the OS only allocated
167.77KB. This might lead to performance problems. Please set your max send
buffer in the OS correctly (e.g. net.core.wmem_max on Linux)
[13:48:24,418][WARN ][jgroups.UDP ] receive buffer of socket
java.net.DatagramSocket@46b29c9d was set to 20MB, but the OS only allocated
524.29KB. This might lead to performance problems. Please set your max
receive buffer in the OS correctly (e.g. net.core.rmem_max on Linux)
[13:48:24,418][WARN ][jgroups.UDP ] send buffer of socket
java.net.MulticastSocket@7846a55e was set to 640KB, but the OS only
allocated 167.77KB. This might lead to performance problems. Please set your
max send buffer in the OS correctly (e.g. net.core.wmem_max on Linux)
[13:48:24,418][WARN ][jgroups.UDP ] receive buffer of socket
java.net.MulticastSocket@7846a55e was set to 25MB, but the OS only allocated
524.29KB. This might lead to performance problems. Please set your max
receive buffer in the OS correctly (e.g. net.core.rmem_max on Linux)
How can I change this buffer in java (not in system, I don't want to change
system values)? I've tried with something like this:
discovery:
jgroups:
config: udp
mcast_send_buf_size: 10000
mcast_recv_buf_size: 10000
ucast_send_buf_size: 10000
ucast_recv_buf_size: 10000
but it didn't work (i had the same values in logs as before) 
I have to get rid of these warnings, because network in my company is
rejecting multicast messages with too many packets - admins sent me logs
like this:
Discard IP fragment set with more than 24 elements: src = 10.1.112.214, dest
= 228.8.8.8, proto = udp, id = 18373
And probably because of this after few minutes of feeding elasticsearch with
data I have logs like this:
[12:28:16,346][WARN ][jgroups.pbcast.NAKACK ] test-4-16470: dropped
message from test-5-22451 (not in xmit_table), keys are [test-4-16470,
test-3-24681, test-2-34614, test-1-48736], view=[test-1-48736|9]
[test-1-48736, test-3-24681, test-4-16470, test-2-34614]
