In trying to protect completed daily indices from future changes, we tried setting index.blocks.read_only : true, but found that we were then unable to query _status, and head plugin could no longer display shard information. I think this best illustrates the behavior we're seeing, but not expecting:

curl -XGET 'http://localhost:9200/messages_20130301/_status'
{"error":"ClusterBlockException[blocked by: [FORBIDDEN/5/index read-only (api)];]","status":403}

Also, as an aside: what's the difference between index.blocks.read_only : true and index.blocks.write : true (which lets me query status and prevents delete?)