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https://issues.apache.org/jira/browse/HDDS-935?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16782888#comment-16782888
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Arpit Agarwal commented on HDDS-935:
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Thanks for updating the patch [~shashikant]. +1 for the v6 patch.
The end-to-end test case looks fine. It would be good to have more isolated
unit test coverage for pieces of the functionality. i.e. making sure newly
created container is saved to the snapshot file and the snapshot file is
correctly loaded on restart, the created containers set remains unchanged
across restart. We can do that in a separate jira.
> Avoid creating an already created container on a datanode in case of disk
> removal followed by datanode restart
> --------------------------------------------------------------------------------------------------------------
>
> Key: HDDS-935
> URL: https://issues.apache.org/jira/browse/HDDS-935
> Project: Hadoop Distributed Data Store
> Issue Type: Improvement
> Components: Ozone Datanode
> Affects Versions: 0.4.0
> Reporter: Rakesh R
> Assignee: Shashikant Banerjee
> Priority: Major
> Attachments: HDDS-935.000.patch, HDDS-935.001.patch,
> HDDS-935.002.patch, HDDS-935.003.patch, HDDS-935.004.patch,
> HDDS-935.005.patch, HDDS-935.006.patch
>
>
> Currently, a container gets created when a writeChunk request comes to
> HddsDispatcher and if the container does not exist already. In case a disk on
> which a container exists gets removed and datanode restarts and now, if a
> writeChunkRequest comes , it might end up creating the same container again
> with an updated BCSID as it won't detect the disk is removed. This won't be
> detected by SCM as well as it will have the latest BCSID. This Jira aims to
> address this issue.
> The proposed fix would be to persist the all the containerIds existing in the
> containerSet when a ratis snapshot is taken in the snapshot file. If the disk
> is removed and dn gets restarted, the container set will be rebuild after
> scanning all the available disks and the the container list stored in the
> snapshot file will give all the containers created in the datanode. The diff
> between these two will give the exact list of containers which were created
> but were not detected after the restart. Any writeChunk request now should
> validate the container Id from the list of missing containers. Also, we need
> to ensure container creation does not happen as part of applyTransaction of
> writeChunk request in Ratis.
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