[
https://issues.apache.org/jira/browse/HDFS-744?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Lars Hofhansl updated HDFS-744:
-------------------------------
Attachment: HDFS-744-trunk-v6.patch
New patch.
* only uses one flag
* SequenceFile.Writer implement Syncable.
* syncFS is deprecated.
* added metrics
* added test using metrics to verify behavior
* added replication test, to make sure the hsync is happening correctly on
replicas.
* found a bug, where sometimes a sync is missed, happens when the currentPacket
in hsync is null. Fixed now.
Currently I count syncs of "out" and "checksumOut" (in BlockReceiver) as two
sync events. Would be hard to do otherwise, as both can be null resp, in which
case no sync is happening.
In rare cases I found that the metrics on the DNs are not updated fast enough,
and a test fails. Looks like there are existing tests that also use metrics
that have the same problem. Not sure what to do about that.
> Support hsync in HDFS
> ---------------------
>
> Key: HDFS-744
> URL: https://issues.apache.org/jira/browse/HDFS-744
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: data-node, hdfs client
> Reporter: Hairong Kuang
> Assignee: Lars Hofhansl
> Attachments: HDFS-744-trunk-v2.patch, HDFS-744-trunk-v3.patch,
> HDFS-744-trunk-v4.patch, HDFS-744-trunk-v5.patch, HDFS-744-trunk-v6.patch,
> HDFS-744-trunk.patch, hdfs-744-v2.txt, hdfs-744-v3.txt, hdfs-744.txt
>
>
> HDFS-731 implements hsync by default as hflush. As descriibed in HADOOP-6313,
> the real expected semantics should be "flushes out to all replicas and all
> replicas have done posix fsync equivalent - ie the OS has flushed it to the
> disk device (but the disk may have it in its cache)." This jira aims to
> implement the expected behaviour.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
