Hi devs,
I am reading through the HA code, trying to understand how the
editlogs propagate.

I have looked at the following classes
EditLogTailer
JournalNode
QuorumJournalManager
NameNode
FSNameSystem

I see FSNameSystem is using FSImage editlog.   where is the tie-in
between  NN and  QuorumJournal?

thanks
Sujee Maniyam

http://sujee.net

Hi Sujee,

QuorumJournalManager implements the JournalManager interface. The javadoc
on JournalManager may help you understand. Also, I would recommend
understanding the local-disk implementation (FileJournalManager) before
digging too deep into the QuorumJournalManager, which is a bit more complex.

-Todd

On Tue, Oct 23, 2012 at 3:31 PM, Sujee Maniyam <[EMAIL PROTECTED]> wrote:

> Hi devs,
> I am reading through the HA code, trying to understand how the
> editlogs propagate.
>
> I have looked at the following classes
> EditLogTailer
> JournalNode
> QuorumJournalManager
> NameNode
> FSNameSystem
>
> I see FSNameSystem is using FSImage editlog.   where is the tie-in
> between  NN and  QuorumJournal?
>
> thanks
> Sujee Maniyam
>
> http://sujee.net
>

--
Todd Lipcon
Software Engineer, Cloudera

Hi Todd,
thanks!

So
FSEditLog.java ::  createJournal(URI uri)
is where a specific journal is chosen.
Config parameters are : dfs.namenode.shared.edits.dir  and
dfs.namenode.edits.journal-plugin

correct?

regards
Sujee

http://sujee.net
On Tue, Oct 23, 2012 at 4:49 PM, Todd Lipcon <[EMAIL PROTECTED]> wrote:
> Hi Sujee,
>
> QuorumJournalManager implements the JournalManager interface. The javadoc
> on JournalManager may help you understand. Also, I would recommend
> understanding the local-disk implementation (FileJournalManager) before
> digging too deep into the QuorumJournalManager, which is a bit more complex.
>
> -Todd
>
> On Tue, Oct 23, 2012 at 3:31 PM, Sujee Maniyam <[EMAIL PROTECTED]> wrote:
>
>> Hi devs,
>> I am reading through the HA code, trying to understand how the
>> editlogs propagate.
>>
>> I have looked at the following classes
>> EditLogTailer
>> JournalNode
>> QuorumJournalManager
>> NameNode
>> FSNameSystem
>>
>> I see FSNameSystem is using FSImage editlog.   where is the tie-in
>> between  NN and  QuorumJournal?
>>
>> thanks
>> Sujee Maniyam
>>
>> http://sujee.net
>>
>
>
>
> --
> Todd Lipcon
> Software Engineer, Cloudera

Yep, that's right.

-Todd

On Wed, Oct 24, 2012 at 4:58 PM, Sujee Maniyam <[EMAIL PROTECTED]> wrote:

> Hi Todd,
> thanks!
>
> So
> FSEditLog.java ::  createJournal(URI uri)
> is where a specific journal is chosen.
> Config parameters are : dfs.namenode.shared.edits.dir  and
> dfs.namenode.edits.journal-plugin
>
> correct?
>
> regards
> Sujee
>
> http://sujee.net
>
>
> On Tue, Oct 23, 2012 at 4:49 PM, Todd Lipcon <[EMAIL PROTECTED]> wrote:
> > Hi Sujee,
> >
> > QuorumJournalManager implements the JournalManager interface. The javadoc
> > on JournalManager may help you understand. Also, I would recommend
> > understanding the local-disk implementation (FileJournalManager) before
> > digging too deep into the QuorumJournalManager, which is a bit more
> complex.
> >
> > -Todd
> >
> > On Tue, Oct 23, 2012 at 3:31 PM, Sujee Maniyam <[EMAIL PROTECTED]> wrote:
> >
> >> Hi devs,
> >> I am reading through the HA code, trying to understand how the
> >> editlogs propagate.
> >>
> >> I have looked at the following classes
> >> EditLogTailer
> >> JournalNode
> >> QuorumJournalManager
> >> NameNode
> >> FSNameSystem
> >>
> >> I see FSNameSystem is using FSImage editlog.   where is the tie-in
> >> between  NN and  QuorumJournal?
> >>
> >> thanks
> >> Sujee Maniyam
> >>
> >> http://sujee.net
> >>
> >
> >
> >
> > --
> > Todd Lipcon
> > Software Engineer, Cloudera
>

--
Todd Lipcon
Software Engineer, Cloudera