If you’re writing GemFire cache.xml files you’ll probably want to refer to the GemFire DTD files for valid syntax. These are hosted on gemstone.com but don’t seem to appear in Google searches so I’m putting this blog in place to facilitate finding them.
GemFire 6.6 DTD on gemstone.com (latest version)
Ye Olde GemFire 6.0 DTD (consider an upgrade)