[
https://issues.apache.org/jira/browse/HDFS-2422?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13124766#comment-13124766
]
M. C. Srivas commented on HDFS-2422:
------------------------------------
Konstantin and Todd, should the timeout be short, or long?
>From the NFS FAQ ... http://nfs.sourceforge.net/#faq_e4 ... soft mounts can
>cause silent data corruption, even in the middle of a file, when a brief
>outage occurs. Thus, during recovery, even though the edits-log looks
>up-to-date, it might contain bad pages in the middle.
If you wish to use soft-mounts, then the recovery process should verify all the
logs before picking one of them to use for replay. (I am not sure if there are
CRCs on every record of the edits-log .. are there?)
Otherwise, with soft-mounts, you will hit issues like HDFS-1382.
> The NN should tolerate the same number of low-resource volumes as failed
> volumes
> --------------------------------------------------------------------------------
>
> Key: HDFS-2422
> URL: https://issues.apache.org/jira/browse/HDFS-2422
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: name-node
> Affects Versions: 0.24.0
> Reporter: Jeff Bean
> Assignee: Aaron T. Myers
> Fix For: 0.24.0
>
> Attachments: HDFS-2422.patch
>
>
> We encountered a situation where the namenode dropped into safe mode after a
> temporary outage of an NFS mount.
> At 12:10 the NFS server goes offline
> Oct 8 12:10:05 <namenode> kernel: nfs: server <nfs host> not responding,
> timed out
> This caused the namenode to conclude resource issues:
> 2011-10-08 12:10:34,848 WARN
> org.apache.hadoop.hdfs.server.namenode.NameNodeResourceChecker: Space
> available on volume '<nfs host>' is 0, which is below the configured reserved
> amount 104857600
> Temporary loss of NFS mount shouldn't cause safemode.
--
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
