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MapReduce >> mail # user >> Read namenode data from primary memory


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Re: Read namenode data from primary memory
Nitin,
You have the whole bunch of problems to answer/resolve....

Let me have some research first, then we can discuss the problem...

Thank you !
Leonid
On Tue, May 14, 2013 at 12:43 AM, Nitin Pawar <[EMAIL PROTECTED]>wrote:

> if you want to use savenamespace then yes.
>
> Normally to have a backup copy of the FSImage, previously there was a
> secondary namenode and now there is checkpoint NN. SNN was deprecated but
> later it was undeprecated
>
> the sole purpose of checkpoint NN is to have an rolling copy of the NN
> based on interval you configure.
> Checkpoint Node is the process which is actually responsible for creating
> periodic check points. It downloads fsimage and log edits from the active
> NameNode, merges them locally, and uploads the new image back to the active
> NameNode.
>
> It is also a good practice that you configure multiple directories for
> saving fsimage and editlogs on different disks. (From cloudera blog: By
> storing two copies of the edit log and FSImage, on two separate hard disks,
> a good system administrator can avoid bringing down the NameNode if one of
> those disks fails.)
>
>
>
>
> On Tue, May 14, 2013 at 12:57 PM, Sandeep Nemuri <[EMAIL PROTECTED]>wrote:
>
>> Done Lets say 8hrs !!
>> now every 8hrs do we need to go into safemode ?
>>
>>
>> On Tue, May 14, 2013 at 12:53 PM, Nitin Pawar <[EMAIL PROTECTED]>wrote:
>>
>>> every 5 minutes seems too much.
>>>
>>> why not do a daily or say 8 hours basis
>>>
>>>
>>> On Tue, May 14, 2013 at 12:51 PM, Sandeep Nemuri <[EMAIL PROTECTED]>wrote:
>>>
>>>> I Agree with you Nitin ..
>>>> My Requirement is i want to copy the edits and fsimage from memory for
>>>> every 5mins. How does this works ?
>>>>
>>>>
>>>> On Tue, May 14, 2013 at 12:31 PM, Nitin Pawar <[EMAIL PROTECTED]>wrote:
>>>>
>>>>> if you do not put namenode in safemode that means your namenode can
>>>>> still accept request to write or delete files from hdfs. This may cause
>>>>> your snapshot to be a problematic in case you want to restore from it.
>>>>> Safemode is just an ensuring point that you have a standstill image to
>>>>> snapshot.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Tue, May 14, 2013 at 12:27 PM, Sandeep Nemuri <[EMAIL PROTECTED]
>>>>> > wrote:
>>>>>
>>>>>> Withuot going to safemode can't we get the Namespace ??
>>>>>>
>>>>>>
>>>>>> On Tue, May 14, 2013 at 12:18 PM, Ling Kun <[EMAIL PROTECTED]>wrote:
>>>>>>
>>>>>>> Hi Aditya:
>>>>>>>    This command line may help you:
>>>>>>>
>>>>>>>      hadoop dfsadmin --saveNamespace
>>>>>>>
>>>>>>>      you should firstly perform it in safe mode.
>>>>>>>
>>>>>>>     The corresponding design and implementation is described here:
>>>>>>> https://issues.apache.org/jira/browse/HADOOP-4826
>>>>>>>
>>>>>>>
>>>>>>> yours,
>>>>>>> Ling Kun
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Tue, May 14, 2013 at 2:37 PM, Aditya exalter <
>>>>>>> [EMAIL PROTECTED]> wrote:
>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>>      How to get the namenode data(edits and fsimage) from the main
>>>>>>>> memory(RAM)
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> http://www.lingcc.com
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> --Regards
>>>>>>   Sandeep Nemuri
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Nitin Pawar
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> --Regards
>>>>   Sandeep Nemuri
>>>>
>>>
>>>
>>>
>>> --
>>> Nitin Pawar
>>>
>>
>>
>>
>> --
>> --Regards
>>   Sandeep Nemuri
>>
>
>
>
> --
> Nitin Pawar
>