In #33102 we added a warning against using filesystem backups.
Experience has shown that the wording we added was insufficiently
general and open to misinterpretation. This commit reworks it to be
clearer.
This commit also clarifies that snapshots are not incremental across
repositories.
Today we describe snapshots as "incremental" but their incrementality is
rather different beast from e.g. incremental filesystem backups. With
traditional backups you take a large and relatively infrequent "full"
backup and then a sequence of smaller "incremental" ones, and this whole
sequence of backups is required for a restore so it must be kept around
until at least the next full backup. In contrast, Elasticsearch
snapshots are logically independent and each can be deleted without
affecting the integrity of the others.
This distinction frequently causes confusion amongst newer users, so
this commit clarifies what we mean by "incremental" in the docs.
* Adds table with icons for simplicity.
* Updating table for clarity.
* Changing table formatting and incorporating more feedback.
* Changing table alignment.
* Adding new page for restore snapshot API.
* Improving test cases, lots of edits, and streamlining content.
* Incorporating review suggestions and feedback.
* Specify `index alias` vs `alias`
* Change parameter order
* Provide clarity around regular expression
* Add link to SLM parameters
* Split sentences in example
* Adding link to master node page.
* Updating snapshot/restore pages to align with API changes.
* Fixing texts in delete snapshot page.
* Removing duplicate code sample and making editorial changes.
* Change "deleted" to "delete"
* Incorporating review feedback and making minor editorial changes.
* Remove titleabbrev
* Add paragraph break
* Remove titleabbrev from restore page
* Remove titleabbrev from create page
* Change "Create" to lowercase
* Change API names to lowercase
* Remove extraneous delimiters
* Change "Delete" to lowercase
* Single-sourcing warning and clarifying warning text.
As discussed at https://elastic.slack.com/archives/C0D1XEXEZ/p1586939752242300 is it not possible to restore snapshots taken on newer versions into clusters running lower versions. For example, a snapshot created in a 7.6.0 cluster cannot be restored on a 7.5.0 cluster. This needs to be documented.