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From Oleg Kiorsak <kior...@gmail.com>
Subject Re: what about Slave failing in "Pure-Master Slave" setup?
Date Fri, 18 Jun 2010 14:18:22 GMT


just discovered another issue with "pure Master-Slave"

in 4 out of 5 test it all worked "by the book" - i.e. 
when I kill MASTER, SLAVE accepgts connections and becomes a master...

but tried it out one more tiem and got this

[root@ip-10-195-225-236 bin]# ERROR MasterConnector                - Network
connection between vm://SLAVE#0 and tcp:///10.252.219.112:10001 shutdown:
Channel was inactive for too long: /10.252.219.112:10001
org.apache.activemq.transport.InactivityIOException: Channel was inactive
for too long: /10.252.219.112:10001
	at
org.apache.activemq.transport.InactivityMonitor$4.run(InactivityMonitor.java:168)
	at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)

 
so looks like SLAVE is not going to become a MASTER and the whole thing is
defunct.
???
what am I doing wrong?
(my conf in SLAVE is

...
<masterConnector remoteURI="tcp://10.252.219.112:10001"/>
...

do I need to specify some "timeout" parameters or keepalive or smthng?
(I would of thought by the nature of SLAVE<->MASTER relationships all proper
setting
would be inherent and implied in the link between them... ???)



thanks&cheers
O.K.









Gary Tully wrote:
> 
> This is true, pure master slave is asymmetrical and it requires manual
> intervention to restore the paring once the master fails. There is an
> option
> on the broker to have the master shutdown if the slave fails, but this is
> off by default. The problem is that there is currently no way to have a
> slave connect and play catch up with an already running and active master.
> 
> Most folk use the shared data store fault tolerant strategy. where N
> brokers
> can share a data store (shared file system or jdbc) and one broker gains
> an
> exclusive lock and becomes active. the rest become passive slaves.
> 
> (That said, from looking at the code, the master will carry on (without
> the
> slave) if it fails to replicate an async command but does not stop
> replication on the failure of a  sync command, which is a little bogus. It
> should just ignore the slave if any replication attempt fails. If you have
> a
> use case for pure master slave, please open a jira issue so we can ensure
> a
> master can carry on in the event of a slave failure)
> 
> 
> On 18 June 2010 14:10, Oleg Kiorsak <kiorsak@gmail.com> wrote:
> 
>>
>>
>> One of the benefits of Pure Master Slave are that supposedly it provides
>> some "HA" -
>> namely books, tutorials, wiki site describe that "when MASTER fails
>> SLAVE"
>> becomes a MASTER
>> and clients are smoothly reconnected to it via the virtue of "failover
>> transport"...
>>
>> That is all nice and good, and TRUE (I tested it)
>>
>> But the question arises - what if its the SLAVE one that fails (as it is
>> a
>> 50/50 chance)...
>>
>> In my testing (when I "kill -KILL") the SLAVE's process the end result is
>> that MASTER just stops accepting any connections and even the queues even
>> disappear from JMX jConsole....
>>
>> only the restart of both restores "status quo"... but restart is
>> something
>> that has to be done manually...
>>
>>
>> so as far as "HA" the solution seems to be asymmetrical - is is only an
>> "HA"
>> when it is the MASTER that fails first...
>>
>> Am I missing something?
>>
>> ???
>>
>> Is there maybe some way to configure it so that MASTER continues to
>> work...
>> alone (just as the SLAVE would if MASTER failed)...
>> ??
>>
>>
>> cheers,
>> O.K.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> --
>> View this message in context:
>> http://old.nabble.com/what-about-Slave-failing-in-%22Pure-Master-Slave%22-setup--tp28925866p28925866.html
>> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>>
>>
> 
> 
> -- 
> http://blog.garytully.com
> 
> Open Source Integration
> http://fusesource.com
> 
> 

-- 
View this message in context: http://old.nabble.com/what-about-Slave-failing-in-%22Pure-Master-Slave%22-setup--tp28925866p28926658.html
Sent from the ActiveMQ - User mailing list archive at Nabble.com.


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