Upgrade & Migration

Moving a running cluster to a newer version, or to another edition, without losing data or availability.

Two pages describe the rules that the remaining pages depend on. Version compatibility covers which versions may run beside each other and what happens when they do not. Order of upgrade applies those rules and describes the sequence in which the components are upgraded.

An upgrade starts with pre-upgrade checks: what has to be true about the cluster, and what has to be safe on a separate machine, before the first package is replaced. In MooseFS PRO PRO (PRO Edition only), a cluster with several Master Servers can go through the whole sequence while the cluster keeps serving data. This procedure is called a rolling upgrade. When an upgrade has to be undone, rollback covers what can be reversed and what cannot.

Two pages cover changes larger than a version upgrade. CE and PRO covers moving between editions in either direction, including what happens to data and Storage Classes that were created under PRO. What changed in 5.x covers what an administrator coming from version 4 has to know before planning the move.

The release-by-release record of what changed is in Release notes.