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Re: Question about HA and FederationESGLinux 2012-12-20, 18:03
Thank you very much,
your answer have clarified me these concepts very much, I didn't understand how could I mix HA and Federation and how many nodes I need.... Kind Regards, ESGLinux, 2012/12/20 Harsh J <[EMAIL PROTECTED]> > 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 > |