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https://issues.apache.org/jira/browse/HDFS-5443?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13813777#comment-13813777
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Vinay commented on HDFS-5443:
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bq. 1. recording extra information in fsimage to indicate INodeFileUC that are
only in snapshots
These extra information only kept as snapshot leases. It will keep track all
the time instead of only at the time of checkpointing. Also it will keep
bq. 2. re-generating all the INodeFileUC when loading fsimage
This will happen as loading leases. and also blocksmap will be updated with
UNDERCONSTRUCTION state
bq. 3. using a similar workaround as in HDFS-5283.
As we already excluding under construction blocks, this workaround no more
required.
bq. To avoid the incompatibility of fsimage, we can put the extra information
to the "under construction files" section of the fsimage.
Yes. exactly because of this reason I went for the approach of storing these
files as leases. Because this section will be
stored from the leases and leases will be loaded from this section.
> Namenode can stuck in safemode on restart if it crashes just after addblock
> logsync and after taking snapshot for such file.
> ----------------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-5443
> URL: https://issues.apache.org/jira/browse/HDFS-5443
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: snapshots
> Affects Versions: 3.0.0, 2.2.0
> Reporter: Uma Maheswara Rao G
> Assignee: sathish
> Attachments: 5443-test.patch
>
>
> This issue is reported by Prakash and Sathish.
> On looking into the issue following things are happening.
> .
> 1) Client added block at NN and just did logsync
> So, NN has block ID persisted.
> 2)Before returning addblock response to client take a snapshot for root or
> parent directories for that file
> 3) Delete parent directory for that file
> 4) Now crash the NN with out responding success to client for that addBlock
> call
> Now on restart of the Namenode, it will stuck in safemode.
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