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From Konstantin Shvachko <shv.had...@gmail.com>
Subject Re: [Discuss] Merge federation branch HDFS-1052 into trunk
Date Wed, 27 Apr 2011 05:36:32 GMT
Dhruba,

It would be very valuable for the community to share your experience
if you performed any independent testing of the federation branch.

Thanks,
--Konstantin

On Tue, Apr 26, 2011 at 9:27 PM, Dhruba Borthakur <dhruba@gmail.com> wrote:

> I feel that making the datanode talk to multiple namenodes is very
> valuable,
> especially when there is plenty of storage available on a single datanode
> machine (think 24 TB to 36 TB) and a single namenode does not have enough
> memory to hold all file metadata for such a large cluster in memory.
>
> This is a feature that we are in dire need of, and could put it to good use
> starting "yesterday"!
>
> thanks,
> dhruba
>
> On Tue, Apr 26, 2011 at 5:59 PM, Konstantin Boudnik <cos@apache.org>
> wrote:
>
> > Sanjay,
> >
> > I assume the outlined changes won't an earlier version of HDFS from
> > upgrads to the federation version, right?
> >
> > Cos
> >
> > On Tue, Apr 26, 2011 at 17:26, Sanjay Radia <sradia@yahoo-inc.com>
> wrote:
> > >
> > > Changes to the code base
> > >  - The fundamental code change is to extend the notion of block id to
> now
> > > include a block pool id.
> > > - The  NN had little change, the protocols did change to include the
> > block
> > > pool id.
> > > - The DN code did change. Each data structure is now indexed by the
> block
> > > pool id -- while this is a code change, it is architecturally very
> simple
> > > and low risk.
> > > - We also did a fair amount of cleanup of threads used to send block
> > reports
> > > - while it was not strictly necessary to do the cleanup we took the
> extra
> > > effort to pay the technical debt. As Dhruba recently noted, adding
> > support
> > > to send block reports to primary and secondary NN for HA will be now
> much
> > > easier to do.
> >
>
>
>
> --
> Connect to me at http://www.facebook.com/dhruba
>

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