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Re: Question about HA and Federation
ESGLinux 2012-12-20, 17:39
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
>