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https://issues.apache.org/jira/browse/CASSANDRA-3250?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13171465#comment-13171465
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Jonathan Ellis commented on CASSANDRA-3250:
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bq. we need every writer to be able to see already open directories
While it doesn't really matter with the current directory-per-keyspace, syncing
every directory open globally when any sstable is written could be problematic
with CASSANDRA-2749 (especially with leveled compaction, which does lots of
small sstable writes). What's the problem with just having writers sync
directories for files they're writing?
> fsync the directory after new sstable or commit log segment are created
> -----------------------------------------------------------------------
>
> Key: CASSANDRA-3250
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3250
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Zhu Han
> Assignee: Pavel Yaskevich
> Priority: Minor
> Fix For: 1.0.7
>
> Attachments: CASSANDRA-3250.patch
>
>
> The mannual of fsync said:
> bq. Calling fsync() does not necessarily ensure that the entry in
> the directory containing the file has also reached disk. For that an
> explicit fsync() on a file descriptor for the directory is also needed.
> At least on ext4, syncing the directory is a must to have step, as described
> by [1]. Otherwise, the new sstables or commit logs could be missed after
> crash even if itself is synced.
> Unfortunately, JVM does not provide an approach to sync the directory...
> [1]
> http://www.linuxfoundation.org/news-media/blogs/browse/2009/03/don%E2%80%99t-fear-fsync
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