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https://issues.apache.org/jira/browse/HBASE-15339?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15179324#comment-15179324
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Duo Zhang commented on HBASE-15339:
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{quote}
What I imagine we want is to be able to write to block cache if data is not old
kind of thing.
{quote}
So if we support write multiple files in different windows for
DateTieredCompaction, we could just write the data in the newest window into
BlockCache?
> Improve DateTieredCompactionPolicy
> ----------------------------------
>
> Key: HBASE-15339
> URL: https://issues.apache.org/jira/browse/HBASE-15339
> Project: HBase
> Issue Type: Improvement
> Components: Compaction
> Reporter: Duo Zhang
>
> For our MiCloud service, the old data is rarely touched but we still need to
> keep it, so we want to put the data on inexpensive device and reduce
> redundancy using EC to cut down the cost.
> With date based tiered compaction introduced in HBASE-15181, new data and old
> data can be placed in different tier. But the tier boundary moves as time
> lapse so it is still possible that we do compaction on old tier which breaks
> our block moving and EC work.
> So here we want to introduce an "archive tier" to better fit our scenario.
> Add an configuration called "archive unit", for example, year. That means, if
> we find that the tier boundary is already in the previous year, then we reset
> the boundary to the start of year and end of year, and if we want to do
> compaction in this tier, just compact all files into one file. The file will
> never be changed unless we force a major compaction so it is safe to apply EC
> and other cost reducing approach on the file. And we make more tiers before
> this tier year by year.
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