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https://issues.apache.org/jira/browse/HBASE-28216?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17810608#comment-17810608
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ASF GitHub Bot commented on HBASE-28216:
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bbeaudreault commented on PR #5591:
URL: https://github.com/apache/hbase/pull/5591#issuecomment-1909171517
@NihalJain can you take a look? The guts of the change is the same, but I
had to update much of ErasureCodingUtils to use reflection. The tests have been
updated to work in both hadoop3 (verifying the EC management works) and in
hadoop2 (verifying we throw an UnsupportedException)
> HDFS erasure coding support for table data dirs
> -----------------------------------------------
>
> Key: HBASE-28216
> URL: https://issues.apache.org/jira/browse/HBASE-28216
> Project: HBase
> Issue Type: New Feature
> Reporter: Bryan Beaudreault
> Assignee: Bryan Beaudreault
> Priority: Major
> Labels: patch-available
>
> [Erasure
> coding|https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-hdfs/HDFSErasureCoding.html]
> (EC) is a hadoop-3 feature which can drastically reduce storage
> requirements, at the expense of locality. At my company we have a few hbase
> clusters which are extremely data dense and take mostly write traffic, fewer
> reads (cold data). We'd like to reduce the cost of these clusters, and EC is
> a great way to do that since it can reduce replication related storage costs
> by 50%.
> It's possible to enable EC policies on sub directories of HDFS. One can
> manually set this with {{{}hdfs ec -setPolicy -path
> /hbase/data/default/usertable -policy xxxx{}}}. This can work without any
> hbase support.
> One problem with that is a lack of visibility by operators into which tables
> might have EC enabled. I think this is where HBase can help. Here's my
> proposal:
> * Add a new TableDescriptor and ColumnDescriptor field ERASURE_CODING_POLICY
> * In ModifyTableProcedure preflightChecks, if ERASURE_CODING_POLICY is set,
> verify that the requested policy is available and enabled via
> DistributedFileSystem.
> getErasureCodingPolicies().
> * During ModifyTableProcedure, add a new state for
> MODIFY_TABLE_SYNC_ERASURE_CODING_POLICY.
> ** When adding or changing a policy, use DistributedFileSystem.
> setErasureCodingPolicy to sync it for the data and archive dir of that table
> (or column in table)
> ** When removing the property or setting it to empty, use
> DistributedFileSystem.
> unsetErasureCodingPolicy to remove it from the data and archive dir.
> Since this new API is in hadoop-3 only, we'll need to add a reflection
> wrapper class for managing the calls and verifying that the API is available.
> We'll similarly do that API check in preflightChecks.
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