> From: Andreas Neumann <[email protected]> > I guess that includes region splits but also > reassignment of a region after its region server died.
If you are not writing, then you won't see splits. Reassignment does involve writes to META but missing these is less serious than missing a change in table structure. Stack could say more here but I believe the Master will discover inconsistency and repair it. > But they could be rare enough to justify a less efficient > implementation of the WAL. Would it be reasonable to use an > implementation of HLog that - at the price of performance - > persists the WAL to HDFS without relying on append? How would that work if not create/write/close on every WAL commit? Correct me if I'm wrong, but there is no way to guarantee persistence in an HDFS without append except to .close() the file. HBase can do the (near) equivalent of this without requiring any code changes. Set hbase.regionserver.logroll.period to an insanely low value. - Andy
