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From "Ahmad Humayun" <ahmad.hu...@gmail.com>
Subject Re: libhdfs v.s. hadoop's hdfs
Date Thu, 28 Feb 2008 07:38:19 GMT
thanks Arun :)

On Thu, Feb 28, 2008 at 5:04 AM, Arun C Murthy <acm@yahoo-inc.com> wrote:

>
> On Feb 27, 2008, at 11:27 AM, Ahmad Humayun wrote:
>
> > Thanks Arun for the comment :) That actually explains how the
> > libhdfs code
> > is minute.
> >
> > So, okay, does that mean that when using the compiled libhdfs.so,
> > it call
> > dfs code to be run on JVM through JNI? If anyone has played with
> > libhdfs,
> > can they tell that do they somehow have to specify where the
> > original hadoop
> > code is lying while using libhdfs.so
> >
>
> Yes. libhdfs relies on the hadoop jars being specified by the
> CLASSPATH env. variable. Please take a look at hadoop's build.xml,
> specifically the 'test-libhdfs' target to see an example.
>
> Arun
>
> > thanks,
> >
> > regards,
> > Ahmad H.
> >
> > On Thu, Feb 28, 2008 at 12:04 AM, Arun C Murthy <acm@yahoo-inc.com>
> > wrote:
> >
> >> Ahmad,
> >>
> >> On Feb 27, 2008, at 10:44 AM, Ahmad Humayun wrote:
> >>
> >>> Hello everyone,
> >>>
> >>> Apparently no one knew the answer to my question :( Am I looking at
> >>> things
> >>> the right way or nobody has compared the libhdfs code to hdfs? Or
> >>> am I
> >>> completely wrong, libhdfs and hdfs has no difference at all?
> >>>
> >>
> >> libhdfs is a JNI-based wrapper around hdfs, so it invokes the
> >> underlying java apis via JNI. It offers most of the functionality of
> >> hdfs, but I'm not sure it has everything.
> >>
> >> The hdfs java api is here:
> >> http://hadoop.apache.org/core/docs/r0.16.0/api/org/apache/hadoop/fs/
> >> FileSystem.html
> >>
> >> Arun
> >>
> >>> regards,
> >>>
> >>> On Mon, Feb 25, 2008 at 11:07 PM, Ahmad Humayun
> >>> <ahmad.humyn@gmail.com>
> >>> wrote:
> >>>
> >>>> Hi there,
> >>>>
> >>>> I was just playing with libhdfs and couldnt help see the
> >>>> differences it
> >>>> has with the hadoop.dfs package. The hadoop.dfs seems to be much
> >>>> more
> >>>> intensive then ifs c++ counterpart, libhdfs, on the amount of
> >>>> functionality
> >>>> it offers. Hmm.. am I wrong here?....am I looking at things the
> >>>> wrong way?
> >>>> Is libhdfs is cut-down part of hadoop.dfs. If so, what
> >>>> functionality I'll
> >>>> miss out on by using libhdfs.
> >>>>
> >>>> Which files in the hadoop.dfs package provide similar functions as
> >>>> libhdfs. In other words where in the dfs package I should look
> >>>> for an
> >>>> "apples to apples" comparison with the libhdfs.
> >>>>
> >>>>
> >>>> thanks,
> >>>> --
> >>>> Ahmad Humayun
> >>>> Research Assistant
> >>>> Computer Science Dpt., LUMS
> >>>> +92 321 4457315
> >>>
> >>>
> >>>
> >>>
> >>> --
> >>> Ahmad Humayun
> >>> Research Assistant
> >>> Computer Science Dpt., LUMS
> >>> +92 321 4457315
> >>
> >>
> >
> >
> > --
> > Ahmad Humayun
> > Research Assistant
> > Computer Science Dpt., LUMS
> > +92 321 4457315
>
>


-- 
Ahmad Humayun
Research Assistant
Computer Science Dpt., LUMS
+92 321 4457315

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