The new 0.90 supports new field data cache settings, including a "node" level cache, that works across all shards allocated on that node. In order to use it, one need to opt into using it, and then configure it. We can simplify it.

By default, we can always use the "node" level cache, but simply have it default to "resident" or unbounded. Once actual bounds need to be set, all that is needed is to set indices.fielddata.cache.size and/or indices.fielddata.cache.expire.