Lots thanks to David and Sean Busbey, I got it. On Nov 9, 2014, at 10:58, Sean Busbey <[email protected]> wrote:
> On Sat, Nov 8, 2014 at 8:13 PM, mail list <[email protected]> wrote: > >> Hi David, >> >> Thanks for your reply. >> The default block size is 64K, So you mean that after i write enough rows >> which exceeds the block size, then >> the put command will not success? >> >> >> > What version of HDFS? The default block size has been 128MB for all of > Hadoop 2.x and was 64MB for Hadoop 1.x. > > The write ahead log will attempt to roll when you get to 95% of this size > (unless you have changed either the default block size or configured an > alternative write ahead log block size). That will require interaction with > the NameNode. > > -- > Sean
