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https://issues.apache.org/jira/browse/HBASE-3380?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12973824#action_12973824
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Jonathan Gray commented on HBASE-3380:
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bq. the new master doesn't wait long enough for all region servers to checkin
so it goes ahead and split logs
we should add a configuration param, something like
{{hbase.master.wait.on.regionservers.mintostart}}. it will at least be useful
for tests and i think it would be generally useful as well.
bq. I think that we should always check in ZK the number of live region servers
before waiting for them to check in
What we need to do is move away from relying on the heartbeat for check-in.
I'd prefer to punt on this fix until 0.92 and fix the test with above. As for
this bug happening in a production cluster, we've actually taken to increasing
{{hbase.master.wait.on.regionservers.interval}} from default of 3 seconds up to
like 20 seconds. I think a default of 10 seconds is better (will add a delay
in some cases but because of failover / interaction with heartbeat period, we
need to have it larger than that period).
> Master failover can split logs of live servers
> ----------------------------------------------
>
> Key: HBASE-3380
> URL: https://issues.apache.org/jira/browse/HBASE-3380
> Project: HBase
> Issue Type: Bug
> Reporter: Jean-Daniel Cryans
> Priority: Blocker
> Fix For: 0.90.0
>
>
> The reason why TestMasterFailover fails is that when it does the master
> failover, the new master doesn't wait long enough for all region servers to
> checkin so it goes ahead and split logs... which doesn't work because of the
> way lease timeouts work:
> {noformat}
> 2010-12-21 07:30:36,977 DEBUG [Master:0;vesta.apache.org:33170]
> wal.HLogSplitter(256): Splitting hlog 1 of 1:
>
> hdfs://localhost:49187/user/hudson/.logs/vesta.apache.org,38743,1292916616340/vesta.apache.org%3A38743.1292916617204,
> length=0
> 2010-12-21 07:30:36,977 DEBUG [WriterThread-1]
> wal.HLogSplitter$WriterThread(619): Writer thread
> Thread[WriterThread-1,5,main]: starting
> 2010-12-21 07:30:36,977 DEBUG [WriterThread-2]
> wal.HLogSplitter$WriterThread(619): Writer thread
> Thread[WriterThread-2,5,main]: starting
> 2010-12-21 07:30:36,977 INFO [Master:0;vesta.apache.org:33170]
> util.FSUtils(625): Recovering file
>
> hdfs://localhost:49187/user/hudson/.logs/vesta.apache.org,38743,1292916616340/vesta.apache.org%3A38743.1292916617204
> 2010-12-21 07:30:36,979 WARN [IPC Server handler 8 on 49187]
> namenode.FSNamesystem(1122): DIR* NameSystem.startFile:
> failed to create file
> /user/hudson/.logs/vesta.apache.org,38743,1292916616340/vesta.apache.org%3A38743.1292916617204
> for
> DFSClient_hb_m_vesta.apache.org:33170_1292916630791 on client 127.0.0.1,
> because this file is already being created by
> DFSClient_hb_rs_vesta.apache.org,38743,1292916616340_1292916617166 on
> 127.0.0.1
> ...
> 2010-12-21 07:33:44,332 WARN [Master:0;vesta.apache.org:33170]
> util.FSUtils(644): Waited 187354ms for lease recovery on
>
> hdfs://localhost:49187/user/hudson/.logs/vesta.apache.org,38743,1292916616340/vesta.apache.org%3A38743.1292916617204:
> org.apache.hadoop.hdfs.protocol.AlreadyBeingCreatedException: failed to
> create file
>
> /user/hudson/.logs/vesta.apache.org,38743,1292916616340/vesta.apache.org%3A38743.1292916617204
> for DFSClient_hb_m_vesta.apache.org:33170_1292916630791 on client 127.0.0.1,
> because this file is already
> being created by
> DFSClient_hb_rs_vesta.apache.org,38743,1292916616340_1292916617166 on
> 127.0.0.1
> {noformat}
> I think that we should always check in ZK the number of live region servers
> before waiting for them to check in, this way we know how many we should
> expect during failover. There's also a case where we still want to timeout,
> since RS can die during that time, but we should wait a bit longer.
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