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From Chong Zhang <chongz.zh...@gmail.com>
Subject Re: tokens and RF for multiple phases of deployment
Date Thu, 31 May 2012 15:46:59 GMT
Thanks Aaron.

I might use LOCAL_QUORUM to avoid the waiting on the ack from DC2.

Another question, after I setup a new node with token +1 in a new DC,  and
updated a CF with RF {DC1:2, DC2:1}. When i update a column on one node in
DC1, it's also updated in the new node in DC2. But all the other rows are
not in the new node. Do I need to copy the data files from a node in DC1 to
the new node?

The ring (2 in DC1, 1 in DC2) looks OK, but the load on the new node in DC2
is almost 0%.

Address         DC          Rack        Status State   Load            Owns
   Token

   85070591730234615865843651857942052864
10.10.10.1    DC1         RAC1        Up     Normal  313.99 MB       50.00%
 0
10.10.10.3    DC2         RAC1        Up     Normal  7.07 MB
0.00%   1
10.10.10.2    DC1         RAC1        Up     Normal  288.91 MB       50.00%
 85070591730234615865843651857942052864

Thanks,
Chong

On Thu, May 31, 2012 at 5:48 AM, aaron morton <aaron@thelastpickle.com>wrote:

>
> Could you provide some guide on how to assign the tokens in this growing
> deployment phases?
>
>
> background
> http://www.datastax.com/docs/1.0/install/cluster_init#calculating-tokens-for-a-multi-data-center-cluster
>
> Start with tokens for a 4 node cluster. Add the next 4 between between
> each of the ranges. Add 8 in the new DC to have the same tokens as the
> first DC +1
>
> Also if we use the same RF (3) in both DC, and use EACH_QUORUM for write
> and LOCAL_QUORUM for read, can the read also reach to the 2nd cluster?
>
> No. It will fail if there are not enough nodes available in the first DC.
>
> We'd like to keep both write and read on the same cluster.
>
> Writes go to all replicas. Using EACH_QUORUM means the client in the first
> DC will be waiting for the quorum from the second DC to ack the write.
>
>
> Cheers
>   -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>
> On 31/05/2012, at 3:20 AM, Chong Zhang wrote:
>
> Hi all,
>
> We are planning to deploy a small cluster with 4 nodes in one DC first,
> and will expend that to 8 nodes, then add another DC with 8 nodes for fail
> over (not active-active), so all the traffic will go to the 1st cluster,
> and switch to 2nd cluster if the whole 1st cluster is down or
> on maintenance.
>
> Could you provide some guide on how to assign the tokens in this growing
> deployment phases? I looked at some docs but not very clear on how to
> assign tokens on the fail-over case.
> Also if we use the same RF (3) in both DC, and use EACH_QUORUM for write
> and LOCAL_QUORUM for read, can the read also reach to the 2nd cluster?
> We'd like to keep both write and read on the same cluster.
>
> Thanks in advance,
> Chong
>
>
>

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