Synced flush was a brilliant idea. It supports instant recoveries with a
quite small implementation. However, with the presence of sequence
numbers and retention leases, it is no longer needed. This change
removes it from 8.0.
Relates #5077
We do mention that rolling back an upgrade requires a restore from a snapshot,
but it's hidden at the bottom of the "preparing to upgrade" instructions on a
different page from the actual upgrade instructions. This commit duplicates the
preparatory instructions onto the pages containing the actual upgrade
instructions and rewords the point about rollbacks a bit.
A few places in the documentation had mentioned 6.7 as the version to
upgrade from, when doing an upgrade to 7.0. While this is technically
possible, this commit will replace all those mentions to 6.8, as this is
the latest version with the latest bugfixes, deprecation checks and
ugprade assistant features - which should be the one used for upgrades.
Co-Authored-By: James Rodewig <james.rodewig@elastic.co>
This commit overhauls the documentation of discovery and cluster coordination,
removing mention of the Zen Discovery module and replacing it with docs for the
new cluster coordination mechanism introduced in 7.0.
Relates #32006
Tweak the upgrade instructions for moving from pre-6.3-with-x-pack to
post-6.3-default distribution. Specifically, you have to remove the
x-pack plugin before upgrading because 6.4 doesn't understand how to
remove it.
Relates to #34307
Since we disable allocation using persistent settings, we should be consistent and remove
the setting from the persistent storage. Otherwise an accidental restart will leed for shards
not being allocated.
Relates to https://github.com/elastic/elasticsearch/pull/28757
James Rodewig
Nhat Nguyen
David Turner
James Rodewig
Alexander Reelsen
Lisa Cawley
debadair
Nik Everett
Boaz Leskes