Until you issue a finalize command, the pre-upgrade metadata is kept aside for rolling back. When you issue the rollback command, it replaces the past metadata files back.
On Fri, Oct 17, 2014 at 5:45 AM, Manoj Samel <[email protected]> wrote: > Hadoop 2.4.0 mentions that FSImage is stored using protobuf. So upgrade from > 2.3.0 to 2.4 would work since 2.4 can read old (2.3) binary format and write > the new 2.4 protobuf format. > > After using 2.4, if there is a need to downgrade back to 2.3, how would that > work ? > > Thanks, -- Harsh J
