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From Mohammad Tariq <donta...@gmail.com>
Subject Re: Region server failure question
Date Wed, 01 Aug 2012 19:52:42 GMT
Hello Mohit,

     If replication factor is set to some value > 1, then the data is
still present on some other node(perhaps within the same rack or a
different one). And, as far as this post is concerned it tells us
about Write Ahead Logs, i.e data that is still not written onto the
disk. This is different from the data written in HFiles, i.e the
persistent data. If the regionserver fails while the data is still
being written, the data can be recovered by replaying the edits from
the WAL file. Please let me know if you disagree.

    Mohammad Tariq

On Thu, Aug 2, 2012 at 12:11 AM, Mohit Anchlia <mohitanchlia@gmail.com> wrote:
> I was reading blog
> http://www.cloudera.com/blog/2012/07/hbase-log-splitting/ and
> it looks like if region servers fails then all the regions on that region
> servers are unavailable until a regions are assigned to a different region
> server. Does it mean all the key ranges for the failed region server is
> unavailable for reads and writes until regions are available on some other
> region server? If so then how to deal with failures while real time data
> might be flowing into HBase.

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