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From Chris Nauroth <cnaur...@hortonworks.com>
Subject Re: HA Hadoop journal nodes configuration
Date Thu, 08 Jan 2015 23:02:20 GMT
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 <yuzhihong@gmail.com> 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 <raoshashidhar123@gmail.com
> > 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 <yuzhihong@gmail.com> 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 <
>>> raoshashidhar123@gmail.com> 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
>>>>
>>>
>>>
>>
>

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