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From Subrahmanya Harve <subrahmanyaha...@gmail.com>
Subject Re: Data retrieval inconsistent
Date Fri, 11 Nov 2011 03:28:39 GMT
Thanks.
I'm gonna try and use QUORUM to read and/or write and see if data is
returned consistently.


On Thu, Nov 10, 2011 at 3:00 PM, Jeremiah Jordan <
jeremiah.jordan@morningstar.com> wrote:

>  No, that is what I thought you wanted.  I was thinking your machines in
> DC1 had extra disk space or something...
>
> (I stopped replying to the dev list)
>
>
> On 11/10/2011 04:09 PM, Subrahmanya Harve wrote:
>
> Thanks Ed and Jeremiah for that useful info.
> "I am pretty sure the way you have K1 configured it will be placed across
> both DC's as if you had large ring.  If you want it only in DC1 you need to
> say DC1:1, DC2:0."
> Infact i do want K1 to be available across both DCs as if i had a large
> ring. I just do not want them to replicate over across DCs. Also i did try
> doing it like you said DC1:1, DC2:0 but wont that mean that, all my data
> goes into DC1 irrespective of whether the data is getting into the nodes of
> DC1 or DC2, thereby creating a "hot DC"? Since the volume of data for this
> case is huge, that might create a load imbalance on DC1? (Am i missing
> something?)
>
>
> On Thu, Nov 10, 2011 at 1:30 PM, Jeremiah Jordan <
> jeremiah.jordan@morningstar.com> wrote:
>
> > I am pretty sure the way you have K1 configured it will be placed across
> > both DC's as if you had large ring.  If you want it only in DC1 you need
> to
> > say DC1:1, DC2:0.
> > If you are writing and reading at ONE you are not guaranteed to get the
> > data if RF > 1.  If RF = 2, and you write with ONE, you data could be
> > written to server 1, and then read from server 2 before it gets over
> there.
> >
> > The differing on server times will only really matter for TTL's.  Most
> > everything else works off comparing user supplied times.
> >
> > -Jeremiah
> >
> >
> > On 11/10/2011 02:27 PM, Subrahmanya Harve wrote:
> >
> >>
> >> I am facing an issue in 0.8.7 cluster -
> >>
> >> - I have two clusters in two DCs (rather one cross dc cluster) and two
> >> keyspaces. But i have only configured one keyspace to replicate data to
> the
> >> other DC and the other keyspace to not replicate over to the other DC.
> >> Basically this is the way i ran the keyspace creation  -
> >>    create keyspace K1 with placement_strategy='org.**
> >> apache.cassandra.locator.**SimpleStrategy' and strategy_options =
> >> [{replication_factor:1}];
> >>    create keyspace K2 with placement_strategy='org.**
> >> apache.cassandra.locator.**NetworkTopologyStrategy' and strategy_options
>
> >> = [{DC1:2, DC2:2}];
> >>
> >> I had to do this because i expect that K1 will get a large volume of
> data
> >> and i do not want this wired over to the other DC.
> >>
> >> I am writing the data at CL=ONE and reading the data at CL=ONE. I am
> >> seeing an issue where sometimes i get the data and other times i do not
> see
> >> the data. Does anyone know what could be going on here?
> >>
> >> A second larger question is  - i am migrating from 0.7.4 to 0.8.7 , i
> can
> >> see that there are large changes in the yaml file, but a specific
> question
> >> i had was - how do i configure disk_access_mode like it used to be in
> 0.7.4?
> >>
> >> One observation i have made is that some nodes of the cross dc cluster
> >> are at different system times. This is something to fix but could this
> be
> >> why data is sometimes retrieved and other times not? Or is there some
> other
> >> thing to it?
> >>
> >> Would appreciate a quick response.
> >>
> >
>
>

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