You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@hbase.apache.org by "stack (JIRA)" <ji...@apache.org> on 2010/11/11 21:40:14 UTC
[jira] Updated: (HBASE-2312) Possible data loss when RS goes into
GC pause while rolling HLog
[ https://issues.apache.org/jira/browse/HBASE-2312?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
stack updated HBASE-2312:
-------------------------
Fix Version/s: (was: 0.90.0)
0.92.0
Moving out of 0.90 after some discussion off-list between Nicolas and Jon. Not having this issue in place means possible "dataloss" (Nicolas)... but Jon comes back "It's data loss only in case where you have a GC pause of death (long enough that the RS is expired) and then I think there's one or two more edge cases that would have to be hit, and then could be data loss."
Leaving the issue critical but not a blocker on 0.90.
> Possible data loss when RS goes into GC pause while rolling HLog
> ----------------------------------------------------------------
>
> Key: HBASE-2312
> URL: https://issues.apache.org/jira/browse/HBASE-2312
> Project: HBase
> Issue Type: Bug
> Components: master, regionserver
> Affects Versions: 0.20.3
> Reporter: Karthik Ranganathan
> Assignee: Nicolas Spiegelberg
> Priority: Critical
> Fix For: 0.92.0
>
>
> There is a very corner case when bad things could happen(ie data loss):
> 1) RS #1 is going to roll its HLog - not yet created the new one, old one will get no more writes
> 2) RS #1 enters GC Pause of Death
> 3) Master lists HLog files of RS#1 that is has to split as RS#1 is dead, starts splitting
> 4) RS #1 wakes up, created the new HLog (previous one was rolled) and appends an edit - which is lost
> The following seems like a possible solution:
> 1) Master detects RS#1 is dead
> 2) The master renames the /hbase/.logs/<regionserver name> directory to something else (say /hbase/.logs/<regionserver name>-dead)
> 3) Add mkdir support (as opposed to mkdirs) to HDFS - so that a file create fails if the directory doesn't exist. Dhruba tells me this is very doable.
> 4) RS#1 comes back up and is not able create the new hlog. It restarts itself.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.