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https://issues.apache.org/jira/browse/HADOOP-834?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12550064
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Craig Macdonald commented on HADOOP-834:
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Hello Dhruba,
I played with your attached NFS implementation for Hadoop NFS. It works well
with 2 caveats:
* Only NFS version 2 is supported (max file size 2GB). This seems a bit low
for typical usage
* No write support - NFS works on random access assumptions, which is
difficult to implement in HDFS - writing files follows the FSDataOutputStream
API.
Before playing with yours, I had been implementing my own HDFS NFS gateway, but
for NFS v3. I think in NFS v3 due to the ability to perform unstable write
operations, the write semantics may be implementable in HDFS. For instance,
caching write operations to the local disk, then replacing a HDFS block at a
time? (Note that the FileSystem API doesnt allow this form of access I think).
Regards
Craig
> Export the HDFS file system through a NFS protocol
> --------------------------------------------------
>
> Key: HADOOP-834
> URL: https://issues.apache.org/jira/browse/HADOOP-834
> Project: Hadoop
> Issue Type: New Feature
> Components: dfs
> Reporter: dhruba borthakur
> Assignee: dhruba borthakur
> Attachments: nfshadoop.tar.gz
>
>
> It would be nice if can expose the HDFS filesystem using the NFS protocol.
> There are a couple of options that I could find:
> 1. Use a user space C-language-implementation of a NFS server and then use
> the libhdfs API to integrate that code with Hadoop. There is such an
> implementation available at
> http://sourceforge.net/project/showfiles.php?group_id=66203.
> 2. Use a user space Java implementation of a NFS server and then integrate
> it with HDFS using Java API. There is such an implementation of NFS server at
> http://void.org/~steven/jnfs/.
> I have experimented with Option 2 and have written a first version of the
> Hadoop integration. I am attaching the code for your preliminary feedback.
> This implementation of the Java NFS server has one limitation: it supports
> UDP only. Some licensing issues will have to be sorted out before it can be
> used. Steve (the writer of the NFS server implemenation) has told me that he
> can change the licensing of the code if needed.
>
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