as described in
and in the recent FB paper, AvatarNode is a different solution as the
BackUpNode/CheckpointNode feature, right?
-----since the link above says: "The HDFS BackupNode is not available
in 0.20, and upgrading our cluster to hadoop 0.20 is not a feasible
option for us because .... ".
if they are different, is the FB AvatarNode feature is open-sourced ?
if so, is it a better or worse solution than the current
BackUpNode/CheckpointNode in apache distribution?