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From Jonathan Gray <jg...@facebook.com>
Subject RE: stopping namenode and regionservers
Date Wed, 06 Oct 2010 06:38:42 GMT
If you can live with restarting your NN, you are living with downtime.  I'd definitely recommend
running your NN on a mirrored RAID so it doesn't get taken out by a single bad disk. 

As you say, stop HBase first if you are the one restarting the NN (not a hardware failure).
 Then you won't lose data.

> -----Original Message-----
> From: Jack Levin [mailto:magnito@gmail.com]
> Sent: Tuesday, October 05, 2010 11:31 PM
> To: user@hbase.apache.org
> Subject: Re: stopping namenode and regionservers
> 
> Many reasons... like broken disk, ram, any sort of hardware
> malfunction, just plain failure of namenode for any reason.
> Generally, I guess I should be stopping regionservers before namenode
> restart, at least I won't generate unflushed data.
> 
> -Jack
> 
> On Tue, Oct 5, 2010 at 11:25 PM, Jonathan Gray <jgray@facebook.com>
> wrote:
> > Currently HBase cannot ride over an HDFS restart.
> >
> > Might be feasible in the future but not currently planned.  Some of
> the NameNode HA solutions might indirectly address this.
> >
> > Why is it that you need to restart your namenode?
> >
> >> -----Original Message-----
> >> From: Jack Levin [mailto:magnito@gmail.com]
> >> Sent: Tuesday, October 05, 2010 10:45 PM
> >> To: user@hbase.apache.org
> >> Subject: stopping namenode and regionservers
> >>
> >> Hi, is it possible to tell regionservers not to die/stop when
> namenode
> >> is restarted?  Every onces in a while I need to restart namenode,
> and
> >> it causes all regionservers pretty much to shutdown, and in many
> cases
> >> not cleanly, which causes long start up delays (hlog, etc).
> >>
> >> Thanks.
> >>
> >> -Jack
> >

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