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From Tamar Fraenkel <ta...@tok-media.com>
Subject Re: increased RF and repair, not working?
Date Mon, 30 Jul 2012 12:16:54 GMT
How do you make this calculation?
Thanks,
*Tamar Fraenkel *
Senior Software Engineer, TOK Media

[image: Inline image 1]

tamar@tok-media.com
Tel:   +972 2 6409736
Mob:  +972 54 8356490
Fax:   +972 2 5612956





On Mon, Jul 30, 2012 at 3:14 PM, Tim Wintle <timwintle@gmail.com> wrote:

> On Mon, 2012-07-30 at 14:40 +0300, Tamar Fraenkel wrote:
> > Hi!
> > To clarify it a bit more,
> > Let's assume the setup is changed to
> > RF=3
> > W_CL=QUORUM (or two for that matter)
> > R_CL=ONE
>
> > The setup will now work for both read and write in case of one node
> > failure.
> > What are the disadvantages, other than the disk space needed to
> > replicate everything trice instead of twice? Will it affect also
> > performance?
>
> (I'm also running RF2, W_CL1, R_CL1 atm - so this is theoretical)
>
> As I understand it, the most significant performance hit will be to the
> variation in response time.
>
> For example with R_CL1, (roughly) 1% of requests will be take more than
> the worst 10% of server response times. With R_CL=QUORUM 2.8% of
> requests will have the same latency. (assuming I've just calculated that
> right)
>
> Tim
>
>
> >
> >
>
>
>

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