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https://issues.apache.org/jira/browse/HBASE-13430?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tobi Vollebregt updated HBASE-13430:
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Attachment: hbase-13430-test.patch
Patch that adds a failing unit test that reproduces the issue.
> HFiles that are in use by a table cloned from a snapshot may be deleted when
> that snapshot is deleted
> -----------------------------------------------------------------------------------------------------
>
> Key: HBASE-13430
> URL: https://issues.apache.org/jira/browse/HBASE-13430
> Project: HBase
> Issue Type: Bug
> Components: hbase
> Reporter: Tobi Vollebregt
> Labels: data-integrity, master
> Attachments: hbase-13430-test.patch
>
>
> We recently had a production issue in which HFiles that were still in use by
> a table were deleted. This appears to have been caused by race conditions in
> the order in which HFileLinks are created, combined with the fact that only
> files younger than {{hbase.master.hfilecleaner.ttl}} are kept alive.
> This is how to reproduce:
> * Clone a large snapshot into a new table. The clone operation must take
> more than {{hbase.master.hfilecleaner.ttl}} time to guarantee data loss.
> * Ensure that no other table or snapshot is referencing the HFiles used by
> the new table.
> * Delete the snapshot. This breaks the table.
> The main cause is this:
> * Cloning a snapshot creates the table in the {{HBASE_TEMP_DIRECTORY}}.
> * However, it immediately creates back references to the HFileLinks that it
> creates for the table in the archive directory.
> * HFileLinkCleaner does not check the {{HBASE_TEMP_DIRECTORY}}, so it
> considers all those back references deletable.
> * The only thing that keeps them alive is the TimeToLiveHFileCleaner, but
> only for 5 minutes.
> * So if cloning the snapshot takes more than 5 minutes, and the HFiles
> aren't referenced by anything else, data loss is guaranteed.
> I have a unit test reproducing the issue and I tried to fix this, but didn't
> completely succeed. I will attach the patch shortly.
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