Hi Gokul,
You're correct that all of the stable released versions of Hadoop have a
buggy implemention of append, and thus dfs.support.append is disabled in
0.20.
The new implementation of append has been tracked in HDFS-265 and is now
complete in trunk - just a few more tests are being done on it at this
point. Major props to the team at Yahoo for the work here! We'll have to
wait some time before this new implementation is available in an Apache
release - see the ongoing release thread on -general for more information on
the timeline.
Regarding ports of append into an 0.20 branch, we will be working on adding
just hflush() functionality to our distribution (CDH) in CDH3, for the
benefit of HBase. This distribution should be available within the next
couple of months. The patches to track are HDFS-200, HDFS-142, and a number
of other bug fixes on top of those. Please get in touch with me off list if
you're interested in testing development builds with this functionality
before it is generally available.
Thanks
-Todd
On Mon, Mar 29, 2010 at 9:01 PM, Gokulakannan M gok...@huawei.com wrote:
Hi,
I am new to hadoop. The following questions popped up in my mind
and I couldn't get answers from web.
I found that in hdfs-default.xml, the property
dfs.support.append has been set to false by default with the description
Does HDFS allow appends to files? This is currently set to
false because there are bugs in the append code and is not supported in
any production cluster
So, is there a way to resolve this issue? any existing
patches(like HADOOP-1700
http://issues.apache.org/jira/browse/HADOOP-1700?page=com.atlassian.jira.pl
ugin.system.issuetabpanels%3Aall-tabpanel ) will solve the problem of
hadoop-append to be stable?
From HADOOP-1700
http://issues.apache.org/jira/browse/HADOOP-1700?page=com.atlassian.jira.pl
ugin.system.issuetabpanels%3Aall-tabpanel , I can see that this feature
has been enabled and updated in trunk. But why it is not enabled in the
stable Hadoop release?
Thanks,
Gokul
--
Todd Lipcon
Software Engineer, Cloudera
