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From: Gokul Prasad <nhgokulprasad@gmail.com>
Date: Sat, 24 Sep 2011 22:02:45 +0530
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 <CAG+qNcSKCSqq_7a1-TjdG4TB4eAVvhC0S5LHn-XypkE_a=KYQQ@mail.gmail.com>
Subject: Re: hadoop high availability using terracotta
To: hdfs-user@hadoop.apache.org
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afaik..drbd approach will take longer to bring standby namenode to
live..am trying to minimise the downtime..like standby namenode will
be relayed with the necessary info thro terracotta and if primary
namenode goes down standby will take its role.

-gokul

On Sat, Sep 24, 2011 at 1:00 AM, GOEKE, MATTHEW (AG/1000)
<matthew.goeke@monsanto.com> wrote:
> Is there any reason not to just use something as simple as drbd (which is=
 baked into vanilla linux)? Unless you are already paying terracotta for th=
eir software there are plenty of HA setups that are supported through the u=
se of drbd and a virtual ip.
>
> Matt
>
> -----Original Message-----
> From: Gokul Prasad [mailto:nhgokulprasad@gmail.com]
> Sent: Friday, September 23, 2011 2:06 PM
> To: hdfs-user@hadoop.apache.org
> Subject: Re: hadoop high availability using terracotta
>
> Cos,
>
> Am planning to implement this idea in bigger cluster but first i want
> to get confidence in small cluster. I do read about terracotta and
> inspired by this idea.
>
> -gokul
>
> On Fri, Sep 23, 2011 at 11:57 PM, Konstantin Boudnik <cos@apache.org> wro=
te:
>> Gokul,
>>
>> Terracotta is a fascinating framework which might be a bit of an oversho=
t for a
>> small setup as well as adding another level of complexity in the form
>> Terracotta framework.
>>
>> Quite interesting approach for NN's HA is Jini (aka ASF River) along wit=
h
>> JavaSpaces for the distributed storage of the meta-data. Using Jini also=
 gives
>> you for free such benefits as auto-discovering making hot-swap of NN a n=
on-issue.
>>
>> I've been musing over this idea for some time and am trying to find some=
 time
>> to actually experiment with it.
>>
>> Cos
>>
>> On Fri, Sep 23, 2011 at 11:36PM, Gokul Prasad wrote:
>>> =A0 =A0Hi,
>>> =A0 =A0Am trying to bring high availability in namenode(in hadoop clust=
er) for
>>> =A0 =A0small setup.
>>> =A0 =A0So the idea is to keep one extra namenode and use terracotta to =
replicate
>>> =A0 =A0the log(in memory details-jvm) from primary datacode to standby =
namenode,
>>> =A0 =A0if primary goes down secondary can take the primary role.
>>> =A0 =A0Now am bit confused how to start second namenode while the prima=
ry name
>>> =A0 =A0node up and running(with datanode connected) with keep relying t=
he info
>>> =A0 =A0from primary thro terracotta. Is there a way to achieve this wit=
hout
>>> =A0 =A0restarting namenode or datanode, any patch?
>>> =A0 =A0Please help and suggest me.
>>> =A0 =A0Regards,
>>> =A0 =A0Gokul
>>
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