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From lars hofhansl <la...@apache.org>
Subject Re: persistence in Hbase
Date Fri, 11 Jan 2013 03:47:30 GMT
The answer here is actually not so simple.
Durable sync was only added to HDFS with HDFS-744, and I have not gotten to make matching
changes to HBase, yet.

Before HDFS-744 there was only hflush, which guarantees that the data reached all replica
datanodes (3 by default), but not that the data is actually sync'ed to disk.
If you now hard shut down (by pulling the powercord for example) three or more machines of
your cluster at the same time you can possibly loose data.

I blogged about this here: http://hadoop-hbase.blogspot.com/2012/05/hbase-hdfs-and-durable-sync.html

-- Lars
From: Panshul Gupta <panshul007@gmail.com>
To: user@hbase.apache.org 
Sent: Thursday, January 10, 2013 7:18 AM
Subject: persistence in Hbase


I was wondering if it is possible that I have data stored in Hbase tables
on my 10 node cluster. I switch off (power down) my cluster. When I power
up my cluster again, and run the HDFS and hadoop daemons, will the Hbase
have my old data persisted in the form I left it?? or will I have to re
import all the data??

Thankyou for the help.


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