Hi, I think you're right and documentation need to be updated.
The 3rd replica is written on a random node in the same rack as the 2nd replica. I will double check. Can you please open a JIRA so this is updated? JM 2013/4/4 KIM JUN YOUNG <[email protected]>: > Hi All. > > There is confused understanding about region-regionser locality. > > from the current document , > > http://hbase.apache.org/book/regions.arch.html > 9.7.3. Region-RegionServer Locality > Over time, Region-RegionServer locality is achieved via HDFS block > replication. The HDFS client does the following by default when choosing > locations to write replicas: > > First replica is written to local node > Second replica is written to another node in same rack > Third replica is written to a node in another rack (if sufficient nodes) > > > but, my understanding is different > HDFS write blocks for replica > > first, local node > second, another node in another rack > third, random another node in same rack > > need to be changed? or am I missing something?
