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Posted to user@hbase.apache.org by y_...@tsmc.com on 2009/08/25 08:20:48 UTC

Loss data while region server crashed ?

Hi there,

While a region server crashed, there's still some data doesn't flush to
storefile.
These data will loss if that region server can't restart any more.
Is that correct?

Fleming
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Re: Loss data while region server crashed ?

Posted by Jean-Daniel Cryans <jd...@apache.org>.
This question was answered not long ago on this mailing list.
Basically, HBase writes to a write ahead log on each region server. We
append all edits in those WALs. When a RS crashes, currently the
master replay those logs (we want to distribute that).

Unfortunately, HDFS doesn't support appends until presumably 0.21 so
you will lose in the most extreme case ~62MB.

J-D

On Tue, Aug 25, 2009 at 2:20 AM, <y_...@tsmc.com> wrote:
> Hi there,
>
> While a region server crashed, there's still some data doesn't flush to
> storefile.
> These data will loss if that region server can't restart any more.
> Is that correct?
>
> Fleming
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