Is it safe to use toolbox set-read-only true during an upgrade? Like running with read-only during the weekend to prevent anyone from changing data in case we need to do a rollback? What happens with snapshots taken during read-only?
Is this the purpose for the feature or is there some other usefull usecases?
And how does this work in a cluster? Does it have to be set on all nodes?
The read-only sets the underlying index in read-only mode, so its guaranteed that no changes will be written to storage.
The setting is cluster-wide, so the whole cluster will be in read only mode.
Snapshots will run as normal, but wont be very useful
