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From Sangmin Lee <sangmin....@gmail.com>
Subject Re: Question regarding HDFS Recovery
Date Wed, 20 May 2009 16:14:19 GMT
I am looking at 0.19.0(or maybe 0.19.1) and 0.20.0.
In fact, I am still curious about the case (maybe too much extream case)
where
a client open a file, request a block and prematurely dies.
Also all datanodes go dead.
I don't see how the lease will be recovered or reaped in this case.
Don't we need some mechanism that discards the block and removes the lease
after several attempts for lease recovery ?

Thanks,
Sangmin

On Wed, May 20, 2009 at 10:40 AM, Edward J. Yoon <edwardyoon@apache.org>wrote:

> Can I ask what version do you read? You looks reach so deeply into the
> architecture of a system...
>
> On Thu, May 21, 2009 at 12:28 AM, Sangmin Lee <sangmin.dev@gmail.com>
> wrote:
> > Okay.. I was going dumb by misreading some source code.
> > Please ignore my question regarding this.
> > Sorry about this.
> >
> > Sangmin
> >
> > On Tue, May 19, 2009 at 11:59 PM, Sangmin Lee <sangmin.dev@gmail.com>
> wrote:
> >
> >> Hi all,
> >>
> >> I have some question regarding the hdfs recovery mechanism.
> >>
> >> I see that INodeFileUnderConstruction has a "targets" field that stores
> >> list of datanodes which store its last block.
> >> However, I don't see them being used at all except that
> >> "internalReleaseLease" function uses the length of the datanode list.
> >> Is there any other use of the "target" fields rather than checking its
> >> length?
> >>
> >> Could anyone shed some light on this?
> >>
> >> Thanks,
> >> Sangmin
> >>
> >
>
>
>
> --
> Best Regards, Edward J. Yoon @ NHN, corp.
> edwardyoon@apache.org
> http://blog.udanax.org
>

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