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https://issues.apache.org/jira/browse/HADOOP-1700?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12525483
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Doug Cutting commented on HADOOP-1700:
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> sameer: [ ... ] but the corner cases when a client dies in the middle of a
> write could be trickier to handle.
Yes, that worries me. I'd be more comfortable sending a new version per flush,
so that we have some atomic ground to stand on. Perhaps we can address clock
skew by, as you suggest, using revisions rather than timestamps. The namenode
need not be involved in the allocation of each revision, only in initializing
the revision counter for a modification sequence. After that, the DFSClient
can increment the revision for each buffer. Do we lose anything by not using
timestamps? We could avoid collisions of blockid+revision with the filesystem
id, no?
> eric: the next logical step here is for us to outline a more detail proposal
Yep. That'd be good. +1
> Append to files in HDFS
> -----------------------
>
> Key: HADOOP-1700
> URL: https://issues.apache.org/jira/browse/HADOOP-1700
> Project: Hadoop
> Issue Type: New Feature
> Components: dfs
> Reporter: stack
>
> Request for being able to append to files in HDFS has been raised a couple of
> times on the list of late. For one example, see
> http://www.nabble.com/HDFS%2C-appending-writes-status-tf3848237.html#a10916193.
> Other mail describes folks' workarounds because this feature is lacking:
> e.g. http://www.nabble.com/Loading-data-into-HDFS-tf4200003.html#a12039480
> (Later on this thread, Jim Kellerman re-raises the HBase need of this
> feature). HADOOP-337 'DFS files should be appendable' makes mention of file
> append but it was opened early in the life of HDFS when the focus was more on
> implementing the basics rather than adding new features. Interest fizzled.
> Because HADOOP-337 is also a bit of a grab-bag -- it includes truncation and
> being able to concurrently read/write -- rather than try and breathe new life
> into HADOOP-337, instead, here is a new issue focused on file append.
> Ultimately, being able to do as the google GFS paper describes -- having
> multiple concurrent clients making 'Atomic Record Append' to a single file
> would be sweet but at least for a first cut at this feature, IMO, a single
> client appending to a single HDFS file letting the application manage the
> access would be sufficent.
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