Another source of information is the Apache documentation on high availability with QJM:
http://hadoop.apache.org/docs/r2.6.0/hadoop-project-dist/hadoop-hdfs/HDFSHighAvailabilityWithQJM.html That page's section on Hardware resources also has a direct answer to your last question about whether or not a SecondaryNameNode is required. Copy-pasting: Note that, in an HA cluster, the Standby NameNode also performs checkpoints of the namespace state, and thus it is not necessary to run a Secondary NameNode, CheckpointNode, or BackupNode in an HA cluster. In fact, to do so would be an error. Chris Nauroth Hortonworks http://hortonworks.com/ On Wed, Jan 7, 2015 at 9:05 PM, Ted Yu <[email protected]> wrote: > Please see > http://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.1-latest/bk_system-admin-guide/content/ch_hadoop-ha-3-2.html > Look for 'Standby NameNode' > > Cheers > > On Wed, Jan 7, 2015 at 8:57 PM, Shashidhar Rao <[email protected] > > wrote: > >> Hi, >> Thanks it helped me a lot. But I am not seeing any secondary namenode so >> my question is is Secondary Namenode required in HA Hadoop cluster >> >> Thanks >> Sd >> >> On Thu, Jan 8, 2015 at 9:38 AM, Ted Yu <[email protected]> wrote: >> >>> Please take a look at >>> http://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.1-latest/bk_system-admin-guide/content/ch_hadoop-ha-3-1.html >>> >>> Cheers >>> >>> On Wed, Jan 7, 2015 at 8:00 PM, Shashidhar Rao < >>> [email protected]> wrote: >>> >>>> Hi, >>>> >>>> I want to setup Hadoop HA with 2 NameNodes and journal nodes. But I am >>>> not sure what should be the configuration of journal nodes >>>> >>>> 1. How many journal nodes I need >>>> 2. What should be the machine configuration like RAM, disk size etc >>>> >>>> This is for a fairly small cluster dealing with 20 Terabytes of data. >>>> >>>> Thanks >>>> Sd >>>> >>> >>> >> > -- CONFIDENTIALITY NOTICE NOTICE: This message is intended for the use of the individual or entity to which it is addressed and may contain information that is confidential, privileged and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient, you are hereby notified that any printing, copying, dissemination, distribution, disclosure or forwarding of this communication is strictly prohibited. If you have received this communication in error, please contact the sender immediately and delete it from your system. Thank You.
