Moving shards

[jrmy911]

I found the documentation about moving shards and got through the first steps by enabling maintenance mode.

I haven't got a ton of experience with JSON but I was wondering how I could update the changelog, by_node and by_range. I feel like the documentation "skips" the CLI for this:
To add a shard to a node, add entries like this to the database metadata’s changelog attribute: ["add", "{range}", "{node-name}"]
It goes rather quick on how about to add that fourth node, if using the example in the documentation.

Okay, but how does this translate into a CLI command using curl -X PUT -H "Content-type: application/json" ? That's where my knowledge is limited. I tried different things like:
curl -X PUT -H "Content-type: application/json" http://{hostname}/_node/_local/_dbs/{dbname} -d '["add","{range}","{node-name}"]'
curl -X PUT -H "Content-type: application/json" http://{hostname}/_node/_local/_dbs/{dbname} -d '["add",{range},{node-name}]'

But it eventually fails and it is either invalid JSON or {"error":"bad_request","reason":"Document must be a JSON object"}.
I'm sure I'm not entirely using the correct syntax, but after having gone through CouchDB's documentation (and the JSON API page), I am feeling a bit lost. :)

[big-r81]

Hi,

you need to:

1. download the database metadata document
2. add the following entries to that metadata document
   • add appropriate changelog entries
   • update the by_node entries
   • update the by_range entries
3. Upload the (edited) document back to CouchDB
   $ curl -X PUT http://localhost/_node/_local/_dbs/{name} -d '{...}'

This is an advanced task, sometime it's easier to set up a new cluster and replicate the old data to the new cluster.