Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
MapReduce >> mail # user >> datanode write forwarding


Copy link to this message
-
Re: datanode write forwarding
Hi Jay,

We'll need "real developer" expertise on this, but my understanding of the
documentation is:

Client talks to Name node to get Node/Block assignments,  client then talks
to node 1: write, fwd, node 2: write, fwd, node 3: write, ack node 2, node
2: ack node1, node 1: ack Client and Name Node.

write includes data write and checksum, ack = report success.  The fwd
requests happen AFTER successful write and checksum.

Hope this helps.
Chris

On Tue, Dec 18, 2012 at 3:56 PM, Jay Vyas <[EMAIL PROTECTED]> wrote:

> Hi :
>
> Do data nodes, when they receive write requests, forward the request to
> the next datanode in the chain after appending to a file? Or rather, do the
> write and forward asynchronously and at the same time?
>
> --
> Jay Vyas
> http://jayunit100.blogspot.com
>