Please refer to open/close connection issue in this forum. This does appear to be a loadui/soapui issue as it closes the connection when a fault occurs. A fault return http 500 as a matter of standard, but a fault can indicate normal processing as well as exceptions. When a high number of faults occur the dropping of the connection causes the server to have issues with to many connections. This problem can be recreated with as few as 5 tps burst against a production configured WebSphere instance. A custom java client we wrote with multiple threads does not cause this to break. If there is a way to not have a http 500 drop the connection with a soap fault that would likely resolve the issue.
soap UI raw response. http 500 is the expected response for a soap fault, but dropping a connection is up to the client.
HTTP/1.1 500 Internal Server Error
X-Powered-By: Servlet/3.0
Content-Type: text/xml; charset=UTF-8
Content-Language: en-US
Content-Length: 1028
Connection: Close
Date: Wed, 04 Sep 2013 18:56:47 GMT
<?xml version="1.0" encoding="UTF-8"?><soapenv:Envelope xmlns:soapenv="
http://schemas.xmlsoap.org/soap/envelope/"><soapenv:Body><soapenv:Fault><faultcode>soapenv:Server</faultcode><faultstring>Both MEDS ID and Person SSN cannot be specified. One or the other must be specified.</faultstring><detail><d:ValidationFault xmlns:a="
http://dhcs.ca.gov/services/header" xmlns:b="
http://dhcs.ca.gov/core/location" xmlns:c="
http://niem.gov/niem/structures/2.0" xmlns:d="
http://dhcs.ca.gov/services/fault" xmlns:e="
http://dhcs.ca.gov/services/eligibility" xmlns:f="
http://dhcs.ca.gov/core/member" xmlns:g="
http://niem.gov/niem/domains/immigration/2.1" xmlns:h="
http://dhcs.ca.gov/core/eligibility" xmlns:i="
http://dhcs.ca.gov/core/application" xmlns:j="
http://dhcs.ca.gov/core/common" xmlns="
http://niem.gov/niem/niem-core/2.0"><d:message>Both MEDS ID and Person SSN cannot be specified. One or the other must be specified.</d:message><d:code>25002</d:code></d:ValidationFault></detail></soapenv:Fault></soapenv:Body></soapenv:Envelope>