We recently submitted a bookkeeper namenode journal implementation to HDFS. It's a contrib module of hadoop-hdfs-project/hadoop-hdfs.
See https://svn.apache.org/repos/asf/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/contrib/bkjournal/ To answer your question, if the add fails, then the log operation should throw an exception, and the bookkeeper journal manager should be moved out of rotation. If it is the only active journal manager, this will lead to the namenode crashing. This is because it's better to impede progress, than to allow progress which would be lost in a crash. -Ivan On Thu, Dec 22, 2011 at 04:44:48PM +0800, Dongdong Guo wrote: > I use the bookkeeper to store the namenode transcation log, when i add the > entry to "LedgerHandle", the callback function "AddCallback", if the "rc" is > not "ok", how do i deal with it,
