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From Azuryy Yu <azury...@gmail.com>
Subject Re: hadoop 2.4 using Protobuf - How does downgrade back to 2.3 works ?
Date Tue, 21 Oct 2014 05:54:07 GMT
after upgrade, there are current an previous subdirs in the namenode
metadata directory. so during rollback, just delete current directory and
rename previous to current again.

On Tue, Oct 21, 2014 at 9:27 AM, Manoj Samel <manojsameltech@gmail.com>
wrote:

> Is the pre-upgrade metadata also kept updated with any changes one in
> 2.4.0 ? Or is it just the 2.3.0 snapshot preserved?
>
> Thanks,
>
> On Sat, Oct 18, 2014 at 1:46 PM, Harsh J <harsh@cloudera.com> wrote:
>
>> Until you issue a finalize command, the pre-upgrade metadata is kept
>> aside for rolling back. When you issue the rollback command, it
>> replaces the past metadata files back.
>>
>> On Fri, Oct 17, 2014 at 5:45 AM, Manoj Samel <manojsameltech@gmail.com>
>> wrote:
>> > Hadoop 2.4.0 mentions that FSImage is stored using protobuf. So upgrade
>> from
>> > 2.3.0 to 2.4 would work since 2.4 can read old (2.3) binary format and
>> write
>> > the new 2.4 protobuf format.
>> >
>> > After using 2.4, if there is a need to downgrade back to 2.3, how would
>> that
>> > work ?
>> >
>> > Thanks,
>>
>>
>>
>> --
>> Harsh J
>>
>
>

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