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From Robert Coli <rc...@eventbrite.com>
Subject Re: Multi-DC Environment Question
Date Tue, 03 Jun 2014 17:52:13 GMT
On Fri, May 30, 2014 at 4:08 AM, Vasileios Vlachos <
vasileiosvlachos@gmail.com> wrote:

> Basically you sort of confirmed that if down_time > max_hint_window_in_ms
> the only way to bring DC1 up-to-date is anti-entropy repair.
>

Also, read repair does not help either as we assumed that down_time >
> max_hint_window_in_ms. Please correct me if I am wrong.
>

My understanding is that if you :

1) set read repair chance to 100%
2) read all keys in the keyspace with a client

You would accomplish the same increase in consistency as you would by
running repair.

In cases where this may matter, and your system can handle delivering the
hints, increasing the already-increased-from-old-default-of-1-hour current
default of 3 hours to 6 or more hours gives operators more time to work in
the case of partition or failure. Note that hints are only an optimization,
only repair (and read repair at 100%, I think..) assert any guarantee of
consistency.

=Rob

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