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From Andrew Purtell <apurt...@apache.org>
Subject Re: Some HBase FAQ
Date Tue, 14 Apr 2009 07:39:08 GMT

I hope we can get fail over to backup masters in 0.20. I
know Nitay is working on the groundwork for it. No more
master SPOF would be fantastic.

Also, I want to second that if the master shuts down, the
regionservers will flush and exit. There is no data loss
for a master failure scenario. 

   - Andy

> From: Ryan Rawson <ryanobjc@gmail.com>
> Subject: Re: Some HBase FAQ
> To: hbase-user@hadoop.apache.org
> Date: Tuesday, April 14, 2009, 12:29 AM
> The write-ahead log is to recover in crash scenarios.
> Even if the regionserver crashes, recovery from log
> will save you.
> But even so, during a controlled shutdown, regionserver
> flushes memcache -> disk.  If the master dies, this 
> flush should get your data to persistent disk.
> On Tue, Apr 14, 2009 at 12:24 AM, Puri, Aseem wrote:
> > Actually I read that if HBase master fails cluster
> > will shut down, so I think for that instance if the
> > data in currently memcache will also lost.


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