Not entirely true, though. Data is not sync'ed to disk, but only distributed to all HDFS replicas. During a power outage event across all HDFS failure zones (such as a data center) you can lose data.
-- Lars ----- Original Message ----- From: anil gupta <[email protected]> To: [email protected] Cc: Sent: Thursday, January 10, 2013 2:38 PM Subject: Re: persistence in Hbase Hi Mohammad, If the Write Ahead Log(WAL) is "turned on" then in **NO** case data should be lost. HBase is strongly-consistent. If you know of any case when WAL is turned on and data is lost then IMO that's a Critical bug in HBase. Thanks, Anil Gupta On Thu, Jan 10, 2013 at 7:37 AM, Mohit Anchlia <[email protected]>wrote: > Data also gets written in WAL. See: > > http://hbase.apache.org/book/perf.writing.html > > On Thu, Jan 10, 2013 at 7:36 AM, ramkrishna vasudevan < > [email protected]> wrote: > > > Yes definitely you will get back the data. > > > > Please read the HBase Book that explains things in detail. > > http://hbase.apache.org/book.html. > > > > Regards > > Ram > > > > > > On Thu, Jan 10, 2013 at 8:48 PM, Panshul Gupta <[email protected]> > > wrote: > > > > > Hello, > > > > > > 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. > > > > > > -- > > > Regards, > > > Panshul. > > > http://about.me/panshulgupta > > > > > > -- Thanks & Regards, Anil Gupta
