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Re: Question about HA and Federation
Yes I think its safe to say that - sorry that I missed out SNNs in my
first response (I counted only the regular serving namenodes) :)

On Thu, Dec 20, 2012 at 11:25 PM, ESGLinux <[EMAIL PROTECTED]> wrote:
> Hi again,
>
> So finally the number of nodes are these:
>
> 1 Active NameNode + 1 Passive NameNode (it does the work of the old
> Secondary NameNode) for NS1 NameSpace (these are 2 diferent machines)
> 1 NameNode for NS2 + 1 Secondary NameNode
> 1 NameNode for NS3 + 1 Secondary NameNode
>
> We can say that we need 2 nodes per NameSpace, is that true?
>
> Thanks,
>
> ESGLinux
>
>
>
> 2012/12/20 Harsh J <[EMAIL PROTECTED]>
>>
>> Hi,
>>
>> To put it simply: If you use a NameNode, you need a SecondaryNameNode.
>> In HA-mode, a StandbyNameNode acts as a SecondaryNameNode (so you
>> don't need to run an extra).
>>
>> Either way, you definitely need the checkpoint operation happening and
>> being monitored for.
>>
>> On Thu, Dec 20, 2012 at 11:09 PM, ESGLinux <[EMAIL PROTECTED]> wrote:
>> > Hi Harsh,
>> >
>> > First thank you very much for your answer,
>> >
>> > following your example:
>> >
>> > You have:
>> >
>> > 1 Active NameNode + 1 Passive NameNode (it does the work of the old
>> > Secondary NameNode) for NS1 NameSpace (these are 2 diferent machines)
>> > 1 NameNode for NS2
>> > 1 NameNode for NS3
>> >
>> > but what about the Secondary Name Nodes for NS2 and NS3? or I don´t need
>> > it?
>> > perhaps I´m mixing concepts....
>> >
>> > Thanks again,
>> >
>> > Greetings,
>> >
>> > ESGLinux
>> >
>> >
>> >
>> >
>> > 2012/12/20 Harsh J <[EMAIL PROTECTED]>
>> >>
>> >> Hi ESGLinux,
>> >>
>> >> Federation and HA are two distinct features that share some common
>> >> properties but nothing more. You can turn on HA for any selected
>> >> Namespace but it is not necessarily needed to be that all Namespaces
>> >> have HA.
>> >>
>> >> Perhaps an example will clear it up for you.
>> >>
>> >> I have a local instance that is configured to run several namespaces:
>> >> ns1, ns2, and ns3 (Federated Namespaces).
>> >> The namespace ns1 hosts my HBase tables and is critical to me, so I
>> >> have also turned on HA for this namespace alone.
>> >> The other two namespaces ns2 and ns3 are used only for regular query
>> >> jobs so its not yet very important for me to have HA on it. So I run
>> >> them without HA.
>> >>
>> >> Thus I have 4 NameNode processes in my cluster in all, given my design
>> >> above: (2 NNs under ns1, in HA mode) + (1 NN of ns2) + (1 NN of ns3).
>> >>
>> >> On Thu, Dec 20, 2012 at 10:00 PM, ESGLinux <[EMAIL PROTECTED]> wrote:
>> >> > Hi All,
>> >> >
>> >> > I´m going to test a hadoop cluster and I have a doubt about HA and
>> >> > Federation.
>> >> >
>> >> > With federation I Have a NameNode per namespace and with HA I have an
>> >> > Active
>> >> > NameNode and a standby NameNode.
>> >> >
>> >> > so, as I have sevaral namespaces, do I need an Active NameNode and a
>> >> > standby
>> >> > nameNode per namespace?
>> >> >
>> >> > I have read this documentation but It´s not clear for me :-(
>> >> >
>> >> >
>> >> >
>> >> > https://ccp.cloudera.com/display/CDH4DOC/Introduction+to+Hadoop+High+Availability
>> >> >
>> >> >
>> >> > http://hadoop.apache.org/docs/r0.23.0/hadoop-yarn/hadoop-yarn-site/Federation.html
>> >> >
>> >> > Thanks in advance
>> >> >
>> >> > ESGLinux
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> Harsh J
>> >
>> >
>>
>>
>>
>> --
>> Harsh J
>
>

--
Harsh J