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Ideal values for tickTime and syncLimit

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Ideal values for tickTime and syncLimit

Jai Bheemsen Rao Dhanwada
Hello,

We have a mult dc zk cluster, and all of a sudden we started seeing
timeouts with observers.
while we are investigating the possible network issue, we would like to
understand accepted values for ticket time and synclimit?

The time out is syncLimit * tickTime

currently we have it set to 2 * 60000 = 2 minutes. we would like to
increase the value to 6 minutes.

what is the impact of increasing it?
what are the acceptable limits?

Thank you
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Re: Ideal values for tickTime and syncLimit

Patrick Hunt
On Thu, Mar 23, 2017 at 11:14 PM, Jai Bheemsen Rao Dhanwada <
[hidden email]> wrote:

> Hello,
>
> We have a mult dc zk cluster, and all of a sudden we started seeing
> timeouts with observers.
> while we are investigating the possible network issue, we would like to
> understand accepted values for ticket time and synclimit?
>
> The time out is syncLimit * tickTime
>
> currently we have it set to 2 * 60000 = 2 minutes. we would like to
> increase the value to 6 minutes.
>
>
2 minutes seems incredibly long to me. Such a setting is saying that you
allow the server to fall 2 minutes behind the quorum. Rather than
investigate increasing the limits I'd recommend you figure out why you're
having such terrible latencies btw dcs (I assume that's the issue, could be
something else, e.g. GC pauses, etc......)


> what is the impact of increasing it?
> what are the acceptable limits?
>
>
Typically determined by the max latency you can allow btw changes in your
cluster and when the clients find out about them. IIRC Camille had done
quite a bit of work with ZK and multi-DC. Perhaps she, or others with this
situation, can provide "real world" insight.

Regards,

Patrick


> Thank you
>
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