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From Aaron Turner <synfina...@gmail.com>
Subject Re: 1.1.1 is "repair" still needed ?
Date Tue, 09 Oct 2012 21:49:39 GMT
On Tue, Oct 9, 2012 at 8:56 PM, Oleg Dulin <oleg.dulin@gmail.com> wrote:
> My understanding is that the repair has to happen within gc_grace period.
>
> But in 1.1.1 you can set gc_grace by CF. A couple of my CFs that are
> frequently updated have gc_grace of 1 hour, but we do run a weekly repair.
>
> So the question is, is this still needed ? Do we even need to run nodetool
> repair ?
>
> If gc_grace is 10 days on all other CFs, are we saying that as long as we
> restart that node within the 10 day period we don't need to run nodetool
> repair ?
>
> The reason I bring this up is because repair once in a while runs for more
> than a day on some of these nodes (500+Gigs of data) and it is causing
> slowness with read requests.

My understanding is:

As long as all your nodes are in sync, then the repair isn't needed.
But if you have a tombstone which isn't replicated to all the nodes
for whatever reason, then the data can come back.  Repair just
guarantees that all the nodes that should of gotten the tombstones got
them.


-- 
Aaron Turner
http://synfin.net/         Twitter: @synfinatic
http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix & Windows
Those who would give up essential Liberty, to purchase a little temporary
Safety, deserve neither Liberty nor Safety.
    -- Benjamin Franklin
"carpe diem quam minimum credula postero"

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