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https://issues.apache.org/jira/browse/HBASE-24601?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17156241#comment-17156241
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dark_num commented on HBASE-24601:
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Due to there has been no new reply/review for some time.
[~Ddupg] , [~comnetwork], [~skewdata], could you take a look at it?
> Change default Hfile storage policy from HOT to NONE for HDFS
> -------------------------------------------------------------
>
> Key: HBASE-24601
> URL: https://issues.apache.org/jira/browse/HBASE-24601
> Project: HBase
> Issue Type: Bug
> Components: hadoop3, HFile
> Affects Versions: 2.2.5
> Reporter: dark_num
> Priority: Major
> Attachments: hfile-policy-problem.png
>
>
> The current HBase hfile directory specifies the *HOT* storage strategy by
> default(`hbase.hstore.blockingStoreFiles` ), which is different from the
> default value of HDFS *heterogeneous* strategy now(should be empty)
> It should be set to *NONE* like `hbase.wal.storage.policy`'s default value on
> HBASE-20691, and the reason for modification is the same
> Otherwise, it could have a significant impact because most HDFS Managers
> doesn't know the default value has been changed to *HOT* by hbase, for
> example:
> HDFS manger want to set hfile's dir to ONE_SSD for speed up read, they will
> do:
> {code:java}
> // Set Hbas Hfile dir to ONE_SSD for speed up read
> // The policy that expects all subdirectories to inherit the parent directory
> by default (empty by default)
> bin/hdfs storagepolicies -setStoragePolicy -path /home/hbase/data -policy
> ONE_SSD
> bin/hdfs storagepolicies -setStoragePolicy -path /home/hbase/WALs -policy
> ALL_SSD
> // If we do not change Hbase default setting, we will find this
> bin/hdfs storagepolicies -getStoragePolicy -path
> /home/hbase/data/hbase/meta/xxxx/info
> return "HOT" instead of "ONE_SSD"{code}
> And here is a pic to show the problem ↑:
> !hfile-policy-problem.png!
> However, if Hfile uses the *HOT* strategy by default, then we will find that
> the actually stored directory has been set to HOT, then it will *not inherit*
> the *ONE_SSD* of the parent directory policy, and if we set *NONE* in hbase,
> this is problem can be avoided
> Unless someone sets other values manually, then we believe the operator
> knows what he is doing
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