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https://issues.apache.org/jira/browse/HDFS-1245?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Konstantin Shvachko updated HDFS-1245:
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Attachment: blockIdGenerator.patch
Here is the patch that introduces {{RandomBlockIdGenerator}}. No big changes so
far. The generator is instantiated in {{format()}} method and after loading the
image during regular startup.
I assume that the generator can be chosen during file system formatting, and
then instantiated (always the same for the file system instance) as indicated
in fsimage or VERSION. The latter is not implemented. As I said there is no
need for that logic until other generators appear.
> Plugable block id generation
> -----------------------------
>
> Key: HDFS-1245
> URL: https://issues.apache.org/jira/browse/HDFS-1245
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: namenode
> Reporter: Dmytro Molkov
> Assignee: Dmytro Molkov
> Attachments: blockIdGenerator.patch
>
>
> The idea is to have a way to easily create block id generation engines that
> may fit a certain purpose. One of them could be HDFS-898 started by
> Konstantin, but potentially others.
> We chatted with Dhruba about this for a while and came up with the following
> approach:
> There should be a BlockIDGenerator interface that has following methods:
> void blockAdded(Block)
> void blockRemoved(Block)
> Block nextBlock()
> First two methods are needed for block generation engines that hold a certain
> state. During the restart, when namenode reads the fsimage it will notify
> generator about all the blocks it reads from the image and during runtime
> namenode will notify the generator about block removals on file deletion.
> The instance of the generator will also have a reference to the block
> registry, the interface that BlockManager implements. The only method there
> is __blockExists(Block)__, so that the current random block id generation can
> be implemented, since it needs to check with the block manager if the id is
> already present.
> What does the community think about this proposal?
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