Thankyou..That is very helpfull.. sorry about the thread hijack..i wanted to change subject before last send ..forgot..
thanks again.. i'll be one active user with tons of Qs in the next few months :) -----Original Message----- From: Jean-Daniel Cryans <jdcry...@apache.org> To: user@hbase.apache.org Sent: Thu, Jul 8, 2010 1:58 pm Subject: About data locality (Was: Re: HBase on same boxes as HDFS Data nodes) (changing the subject, let's not hijack threads) > will the data move over time though...for example if i have lots of access to data in DataNode A ? without the current work that is in progress.. HBase has no control on that, but data will be moved if those regions are used. Like the article explains, the first replica goes to the local node, so through compactions/flushes one replica of each block will be on the local node. Also keep in mind that the new datanode may already contain some replicas of some of the blocks for that region, so it's not just black and white. This is quite possible on a small cluster, but over 1k nodes not that much ;) J-D On Thu, Jul 8, 2010 at 10:51 AM, <vramanatha...@aol.com> wrote: > > Thankyou.. > I've some more questions > I'm spending quite a bit over last few weeks to develop one of our applications using HBase/Hadoop > & using 0.20.4 > > Hbase - Table X > rows - 1- 100 -> Region A -> RegionServer A --> DataNode A > .... > rows 1500 - 1600 -> Region M -> RegionServer B -> DataNode B > > So based on what I have read so far..I'm thinking of Region Server A & Data Node A pairs on the same host to > make use of locality.. > > As per your answer ..If we restart the cluster, because of radom assigment, locality is gone > so..Region Server B -..> Region A ---> data blocks will be in Data Node A > ...if I understand correctly.. > will the data move over time though...for example if i have lots of access to data in DataNode A ? without the current work that is in progress.. > > thanks again for your reply > > venkatesh > >
