What do you mean clunky? IMHO this is a quite elegant, simple, working solution. Sure this spawns multiple processes, but it beats any api-overcomplications, imho.
Dieter On Wed, 18 May 2011 11:39:36 -0500 Patrick Angeles <[email protected]> wrote: > kinda clunky but you could do this via shell: > > for $FILE in $LIST_OF_FILES ; do > hadoop fs -copyFromLocal $FILE $DEST_PATH & > done > > If doing this via the Java API, then, yes you will have to use > multiple threads. > > On Wed, May 18, 2011 at 1:04 AM, Mapred Learn > <[email protected]>wrote: > > > Thanks harsh ! > > That means basically both APIs as well as hadoop client commands > > allow only serial writes. > > I was wondering what could be other ways to write data in parallel > > to HDFS other than using multiple parallel threads. > > > > Thanks, > > JJ > > > > Sent from my iPhone > > > > On May 17, 2011, at 10:59 PM, Harsh J <[email protected]> wrote: > > > > > Hello, > > > > > > Adding to Joey's response, copyFromLocal's current implementation > > > is > > serial > > > given a list of files. > > > > > > On Wed, May 18, 2011 at 9:57 AM, Mapred Learn > > > <[email protected]> wrote: > > >> Thanks Joey ! > > >> I will try to find out abt copyFromLocal. Looks like Hadoop Apis > > >> write > > > serially as you pointed out. > > >> > > >> Thanks, > > >> -JJ > > >> > > >> On May 17, 2011, at 8:32 PM, Joey Echeverria <[email protected]> > > >> wrote: > > >> > > >>> The sequence file writer definitely does it serially as you can > > >>> only ever write to the end of a file in Hadoop. > > >>> > > >>> Doing copyFromLocal could write multiple files in parallel (I'm > > >>> not sure if it does or not), but a single file would be written > > >>> serially. > > >>> > > >>> -Joey > > >>> > > >>> On Tue, May 17, 2011 at 5:44 PM, Mapred Learn > > >>> <[email protected]> > > > wrote: > > >>>> Hi, > > >>>> My question is when I run a command from hdfs client, for eg. > > >>>> hadoop > > fs > > >>>> -copyFromLocal or create a sequence file writer in java code > > >>>> and > > append > > >>>> key/values to it through Hadoop APIs, does it internally > > transfer/write > > > data > > >>>> to HDFS serially or in parallel ? > > >>>> > > >>>> Thanks in advance, > > >>>> -JJ > > >>>> > > >>> > > >>> > > >>> > > >>> -- > > >>> Joseph Echeverria > > >>> Cloudera, Inc. > > >>> 443.305.9434 > > >> > > > > > > -- > > > Harsh J > >
