> -----Original Message----- > From: Ski Gh3 [mailto:[EMAIL PROTECTED] > Sent: Tuesday, October 21, 2008 10:43 AM > To: [email protected] > Subject: Re: log replication in hbase > > The last "yes" is contradictary with the previous one... > So I take this redo log is the WAL log?
Yes. > It is written to HDFS (replicated three times) rather than stored on the > regionserver itself locally? Yes. > Thanks! > On Mon, Oct 20, 2008 at 9:33 PM, stack <[EMAIL PROTECTED]> wrote: > > > Ski Gh3 wrote: > > > >> Just want to make sure my understanding of the log is correct: > >> > >> each regionserver has one log for all the regions it is serving. > >> > >> > > > > Yes. > > > > this log is the write-ahead log that is stored on hadoop dfs and > always > >> written before a data is written to memcache. > >> is this correct? > >> > >> > > > > Yes. > > > > I read about a redo log from the mailing list, which says each > >> regionserver > >> maintains a redo log locally. > >> is this the wal log or what is the purpose of this redo log? > >> > >> > > Yes. > > > > Sorry for any confusion. We should be try and be more strict with our > > nomenclature. > > > > St.Ack > > > >
