[
https://issues.apache.org/jira/browse/HDFS-4750?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13642102#comment-13642102
]
Hari Mankude commented on HDFS-4750:
------------------------------------
Implementing writes might not be easy. The client implementations in various
kernels does not guarantee that the writes are issued in sequential order. Page
flushing algorithms try to find contiguous pages (offsets). However, there are
other factors in play with page flushing algorithms. So it does not imply that
writes from the client has to be sequential as HDFS requires it to be. This is
true whether the writes are coming in lazily from the client or due to a sync()
before close(). A possible solution is for nfs gateway on dfs client to cache
and reorder the writes to be sequential. But, this might still result in
"holes" which hdfs cannot handle. Also, the cache requirements might not be
trivial and might require a flush to local disk.
NFS interfaces are very useful for reads.
> Support NFSv3 interface to HDFS
> -------------------------------
>
> Key: HDFS-4750
> URL: https://issues.apache.org/jira/browse/HDFS-4750
> Project: Hadoop HDFS
> Issue Type: New Feature
> Affects Versions: 3.0.0
> Reporter: Brandon Li
> Assignee: Brandon Li
> Attachments: HADOOP-NFS-Proposal.pdf
>
>
> Access HDFS is usually done through HDFS Client or webHDFS. Lack of seamless
> integration with client’s file system makes it difficult for users and
> impossible for some applications to access HDFS. NFS interface support is one
> way for HDFS to have such easy integration.
> This JIRA is to track the NFS protocol support for accessing HDFS. With HDFS
> client, webHDFS and the NFS interface, HDFS will be easier to access and be
> able support more applications and use cases.
> We will upload the design document and the initial implementation.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
