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From Eric Newton <eric.new...@gmail.com>
Subject Re: imbalance in number of zookeeper clients
Date Mon, 14 Sep 2015 22:39:40 GMT
It (unbalanced number of clients) happens, and it's not normally a problem.
In general, Accumulo is a pretty light user of zookeeper. It does add a lot
of watches for table and user configuration (ACCUMULO-2757), but those
things rarely change. If a particular zookeeper node is too bogged down,
the clients will miss heartbeats and reconnect to another server, which
will (eventually) re-balance the load.

-Eric

On Fri, Sep 11, 2015 at 6:21 AM, Jeff Turner <sjtsp2008@gmail.com> wrote:

> i think ACCUMULO-3218 may have bit us two days ago, due to the first
> zookeeper
> in the list being unavailable.
>
> but, after a full restart, i don't think that situation applies - the
> lighter-load zookeeper
> was in the middle of the list - 600, 600, 250, 600, 600.
>
> thanks,
>
>
>
> On 9/10/15 8:02 PM, dlmarion wrote:
>
> Hey Jeff,
>
>  Take a look at [1] and see if the zookeeper balance issue mentioned is
> applicable.
>
> Dave
>
> [1] https://accumulo.apache.org/release_notes/1.6.2.html
>
>
>
>
>
> -------- Original message --------
> From: Jeff Turner <sjtsp2008@gmail.com> <sjtsp2008@gmail.com>
> Date: 09/10/2015 7:42 PM (GMT-05:00)
> To: user@accumulo.apache.org
> Subject: imbalance in number of zookeeper clients
>
> sorry if this is a faq.  i can't come up with a good google query to
> find the answer.
>
> how bad is it that four of our five zookeepers have 600-700 clients, and
> one
> has about 250?
>
> i assumed that zookeeper or accumulo has some sort of natural
> rebalancing property,
> so it will all work itself out.
>
> i've been resisting a full accumulo/zk restart.
> and restarting the one zookeeper to see what happens has a big
> unpleasant wake, too.
>
> so
>    - will they eventually rebalance
>    - if not, how bad is it that four of them are working harder
>
> thanks,
> jeff
>
>
>

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