Revises the current 'How to avoid oversharding' docs to incorporate
information from our [shard sizing blog post][0].
Changes:
* Streamlines introduction
* Adds "Things to remember" section to describe how shards work
* Adds "Guidelines" section based on blog tips
* Creates a "Fix an oversharded cluster" section
[0]: https://www.elastic.co/blog/how-many-shards-should-i-have-in-my-elasticsearch-cluster
This commit corrects the grammar in a list in the how-to docs; namely,
the word "and" was missing preceding the final element in a list.
Relates #22663
This moves the "Performance Considerations for Elasticsearch Indexing" blog post
to the reference guide and adds similar recommendations for tuning disk usage
and search speed.
James Rodewig
James Rodewig
Elijah
Adrien Grand