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From Shushant Arora <shushantaror...@gmail.com>
Subject Re: Hbase master selection doubt
Date Sat, 27 Jun 2015 14:57:00 GMT
By strictly consistent I mean - all clients should see same data at any
time in different sessions.

Say a client C1 was connected to follower F1, And F1 was few seconds behind
the leader. And client C2 connects to F2 which is in sync with Leader . Now
C1 and C2 will see different data under root dir say(/master ) is visible
to C2 not to C1. Till F1 comes in sync with Leader.

On Sat, Jun 27, 2015 at 8:23 PM, Shushant Arora <shushantarora09@gmail.com>
wrote:

> Zookeeper is Sequential Consistency
> Updates from a client will be applied in the order that they were sent.
>
> On Sat, Jun 27, 2015 at 8:18 PM, Ted Yu <yuzhihong@gmail.com> wrote:
>
>> bq. non strictly consistency of Zookeeper
>>
>> Can you elaborate on what the above means ?
>>
>> please read this:
>>
>> http://zookeeper.apache.org/doc/trunk/zookeeperProgrammers.html#ch_zkGuarantees
>>
>> Cheers
>>
>> On Sat, Jun 27, 2015 at 7:20 AM, Shushant Arora <
>> shushantarora09@gmail.com>
>> wrote:
>>
>> > How Hbase uses Zookeeper for Master selection and region server failure
>> > detection when Zookeeper is not strictly consistent.
>> >
>> > Say In Hbase Master selection process, how does a node is 100 % sure
>> that a
>> > master is created ? Does it has to create the /master node and that node
>> > already exists will thow node exists excpetion .  Since only by reading
>> (ls
>> > /) . It may get stale data and gets node does not exists.but in actual
>> > /master was present.
>> >
>> > Does there any issue with non strictly consistency of Zookeeper for
>> Hbase?
>> >
>>
>
>

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