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https://issues.apache.org/jira/browse/HDFS-6339?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13989578#comment-13989578
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Kihwal Lee edited comment on HDFS-6339 at 5/5/14 2:54 PM:
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This is expected.
Upgrade/rollback with HA was not supported until 2.4. So If you are rolling
back from 2.4 HA to a previous version, some manual steps are needed. In this
case, rollback needs to be done with HA off. It means that the shared edits
need to be copied to non-HA name.dir or edits.dir depending on your config. If
the HA NN was configured to also store edits locally, it is a bit easier.
After successfully rolling back, HA can be re-enabled by initializing shared
edits dir and bootstrapping standby. 2NN does not have to persist any state,
so you can safely delete the temporary files.
bq. I fixed this by deleting the JN data directory.
I assume the NN had all edits locally. Otherwise there can be data loss. Other
than this, your procedure seems okay.
In the future, please use mailing lists for the inquiries of this kind.
was (Author: kihwal):
This is expected.
Upgrade/rollback with HA was not supported until 2.4. So If you are rolling
back from 2.4 HA to a previous version, some manual steps are needed. In this
case, rollback needs to be done with HA off. It means that the shared edits
need to be copied to non-HA name.dir or edits.dir depending on your config. If
the HA NN was configured to also store edits locally, it is a bit easier.
After successfully rolling back, HA can be re-enabled by initializing shared
edits dir and bootstrapping standby. 2NN does not have to persist any state,
so you can safely delete the temporary files.
bq. I fixed this by deleting the JN data directory.
I assume the NN had all edits locally. Otherwise there ca be data loss. Other
than this, your procedure seems okay.
In the future, please use mailing lists for the inquiries of this kind.
> DN, SNN & JN can't rollback data
> --------------------------------
>
> Key: HDFS-6339
> URL: https://issues.apache.org/jira/browse/HDFS-6339
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: journal-node
> Affects Versions: 2.2.0
> Reporter: Rahul Singhal
>
> I tried rollback from 2.4.0 to 2.2.0 and noticed that DN, SNN and JN couldn't
> perform rollback.
> I started with a (NN) HA cluster on 2.2.0 and upgraded it to 2.4.0 with HA
> enabled. Then attempted a rollback to 2.2.0. I first configured my cluster to
> non-HA and started it on 2.2.0. I started NN & DN with the '-rollback'
> startup option. (There is no explicit startup option for SNN & JN like NN &
> DN). Only NN was able to rollback correctly.
> My fixes:
> I fixed the DN rollback problem by cherry-picking the fix from HDFS-5526.
> I fixed the SNN rollback problem by starting it with '-format' option.
> I then proceeded to converting the non-HA cluster to a HA cluster. The first
> step after configuration change was to start the JNs. But they also couldn't
> rollback.
> My fix:
> I fixed this by deleting the JN data directory. (deleting the 'current'
> directory and renaming 'previous' to 'current' didn't fix the rollback)
> My purpose for filing this bug is to:
> 1. Ask if these problems are known and intended to be fixed in any future
> releases. If yes, which one? DN rollback was fixed in 2.3.0 but what about
> 2.2.x series? JN rollback seems (not confirmed) to have been fixed in 2.4.0.
> 2. Confirm that "my fixes" are correct. If not, please help me with an
> appropriate fix.
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