elmahio/Elmah.Io.ElasticSearch — pull request #5 by jayhilden (2014-09-12 20:02:03+00:00)
Title: Error writing to ES, error_xml field is too long

IllegalArgumentException[Document contains at least one immense term in field=\"error_xml\"

From this link here I believe we just need to set the index on ErrorXml from "NotAlalyzed" to "No"

http://stackoverflow.com/questions/24019868/utf8-encoding-is-longer-than-the-max-length-32766