Coherence Warning on Oracle Weblogic 12c

 

The error

This was seen on a Oracle Weblogic 12.1.3 server on AIX

PreferredUnicastUdpSocket failed to set receive buffer size to 1444 packets (2MB); actual size is 42%, 609 packets (864KB). Consult your OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performance.>

The fix

To fix this issue, configure your OS to allow for larger buffers.

On Linux execute (as root):

sysctl -w net.core.rmem_max=2096304
sysctl -w net.core.wmem_max=2096304

On AIX execute (as root):

no -op rfc1323=1
no -op sb_max=4194304
no -op udp_recvspace=4194304
no -op udp_sendspace=65536

(Note that AIX only supports specifying receive buffer sizes of 1MB, 4MB, and 8MB)