Metacat

The schema locations is /tomcat-home/webapps/metacat/schema (in order to be accessible by the http), so the new installation of Metacat may delete the schemas added by this page. It will create the scenario - the xml_catalog has the record but the schema file itself has been gone.

The solution I am thinking is the registry process will create two copies of the schema, one is in /tocmat-home/webpass/metacat/schema; the other is in /var/metacat/schema. If the copy of /tocmat-home/webpass/metacat/schema is gone, Metacat can copy it back from /var/metacat/schema.

I think this is a good idea, but I think we should go the other way -- have the copy in wepapps/metacat/schema be the 'shipped' version, and copy those on Metacat start to /var/metacat/schemas, and use that as the official 'local' copy.

This is good idea - we can avoid to create two copies of registered schemas in the registry process and the scenario that registered schemas are deleted. However, the /var/metacat/schemas is not accessible by Apache by default, so we have to set the schema location by the file protocol. Also it is hard for users to look at the schema itself.