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https://issues.apache.org/jira/browse/HBASE-5954?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13532914#comment-13532914
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Varun Sharma commented on HBASE-5954:
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No I am not talking about deferred WAL flush. This is what I know but i maybe
wrong:
1) HBase uses hflush for WAL which ensures that data is in OS buffers and
leaves the data in the hands of the OS - after that the time from OS cache ->
disk persistence is variable
2) With sync, we will synchronize the WAL to disk so there is no data loss
I am asking about the possibility of intermittent sync(s) performed by the
region server every N edits - so N edits where we do hflush and then we do
hsync or every N seconds. Because, going from hflush -> hsync for WAL will kill
performance. If we can have gaurantees that say last 1 or 0.5 second worth of
data is intact and similarly, you can lose 1000 edits in case of power failure
- that is a nice to have.
> Allow proper fsync support for HBase
> ------------------------------------
>
> Key: HBASE-5954
> URL: https://issues.apache.org/jira/browse/HBASE-5954
> Project: HBase
> Issue Type: Improvement
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Attachments: 5954-trunk-hdfs-trunk.txt, 5954-trunk-hdfs-trunk-v2.txt,
> 5954-trunk-hdfs-trunk-v3.txt, 5954-trunk-hdfs-trunk-v4.txt,
> 5954-trunk-hdfs-trunk-v5.txt, 5954-trunk-hdfs-trunk-v6.txt, hbase-hdfs-744.txt
>
>
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