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From Benjamin Reed <br...@yahoo-inc.com>
Subject Re: Regarding Leader election and the limit on number of clients without performance degradation
Date Mon, 12 Jul 2010 22:01:55 GMT
ted is correct, as usual. that warning is really to avoid unnecessary 
load, and 16 clients really don't generate much of a load at all. even 
with thousands of cliets, if they really need the list of children it 
will still be ok. the point of that note was that for leader election 
only one process will emerge, so having a bunch of other processing 
making unneeded requests is wasteful and can be avoided.


On 07/12/2010 01:47 PM, Ted Dunning wrote:
> Having 16 clients all wake up and ping ZK is an extremely light load.  The
> warning on the recipes page had more to do with the situation where
> thousands of nodes wake up at the same time.
> On Mon, Jul 12, 2010 at 1:30 PM, Srikanth Bondalapati:<
> sbondalapati@tagged.com>  wrote:
>> Hi,
>> I am using ZooKeeper service for leader election and group management. I
>> have read in the site (
>> http://hadoop.apache.org/zookeeper/docs/r3.2.2/recipes.html#sc_leaderElection
>> )
>> under the "LeaderElection" section that, if all the clients try to access
>> the getChildren() when trying to become a leader, it causes a bottleneck on
>> the server. But, I wanted to execute getChildren() method on all the
>> clients
>> that have seen a change on the parent's ZNode. So, could you please tell
>> what could be the maximum number of clients that can be used without any
>> performance drop on the server, when all the clients try to execute
>> getChildren() method? Currently, I intend to use 16 clients cluster, and
>> the
>> data on each of the ZNodes is very less (say<  500 bytes).
>> Anxiously waiting for your reply,
>> Thanks&  Regards,
>> Srikanth.

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