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https://issues.apache.org/jira/browse/HBASE-7006?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13658089#comment-13658089
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Jeffrey Zhong commented on HBASE-7006:
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[[email protected]] Thanks! I'll keep working on the follow up items and add
a release note accordingly.
> [MTTR] Improve Region Server Recovery Time - Distributed Log Replay
> -------------------------------------------------------------------
>
> Key: HBASE-7006
> URL: https://issues.apache.org/jira/browse/HBASE-7006
> Project: HBase
> Issue Type: New Feature
> Components: MTTR
> Reporter: stack
> Assignee: Jeffrey Zhong
> Priority: Critical
> Fix For: 0.98.0, 0.95.1
>
> Attachments: hbase-7006-combined.patch, hbase-7006-combined-v1.patch,
> hbase-7006-combined-v4.patch, hbase-7006-combined-v5.patch,
> hbase-7006-combined-v6.patch, hbase-7006-combined-v7.patch,
> hbase-7006-combined-v8.patch, hbase-7006-combined-v9.patch, LogSplitting
> Comparison.pdf,
> ProposaltoimprovelogsplittingprocessregardingtoHBASE-7006-v2.pdf
>
>
> Just saw interesting issue where a cluster went down hard and 30 nodes had
> 1700 WALs to replay. Replay took almost an hour. It looks like it could run
> faster that much of the time is spent zk'ing and nn'ing.
> Putting in 0.96 so it gets a look at least. Can always punt.
> Distributed Log Replay Description:
> After a region server fails, we firstly assign a failed region to another
> region server with recovering state marked in ZooKeeper. Then a
> SplitLogWorker directly replays edits from WAL(Write-Ahead-Log)s of the
> failed region server to the region after it's re-opened in the new location.
> When a region is in recovering state, it can also accept writes but no
> reads(including Append and Increment), region split or merge.
> The feature piggybacks on existing distributed log splitting framework and
> directly replay WAL edits to another region server instead of creating
> recovered.edits files.
> The advantages over existing log splitting recovered edits implementation:
> 1) Eliminate the steps to write and read recovered.edits files. There could
> be thousands of recovered.edits files are created and written concurrently
> during a region server recovery. Many small random writes could degrade the
> overall system performance.
> 2) Allow writes even when a region is in recovering state. It only takes
> seconds for a failed over region to accept writes again.
> The feature can be disabled by setting hbase.master.distributed.log.replay to
> false(by default is true)
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