Most of them are outdated, but provide historical design context.
They are not user documentation and should not be treated as such.
Documentation is available here.
Storage Domain Live Upgrade
This feature will allow upgrades from old data center types to new ones even while the pool is active and VMs are running.
Released in oVirt 3.1
Some features are only available in certain data center levels because of backwards incompatible changes. Up until now you had to create a new data center to enjoy the new features. This feature will allow users to upgrade existing data centers to allow them to use new features.
Data Center level change.
When the user changes the data center compatibility level an upgrade process will initiate in VDSM.
No new scheme is required.
How to use
To initiate a VDSM upgrade either use the
upgradeStoragePool verb or put the new format in the
User work flows
User will be able to changes the data center compatibility level through the UI.
Changes in ovirt engine
Initiate pool upgrade in VDSM when changing data center compatibility level.