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From Casey Deccio <ca...@deccio.net>
Subject Re: adding node to cluster
Date Fri, 31 Aug 2012 05:39:08 GMT
On Thu, Aug 30, 2012 at 11:21 AM, Rob Coli <rcoli@palominodb.com> wrote:

> On Thu, Aug 30, 2012 at 10:18 AM, Casey Deccio <casey@deccio.net> wrote:
> > I'm adding a new node to an existing cluster that uses
> > ByteOrderedPartitioner.  The documentation says that if I don't
> configure a
> > token, then one will be automatically generated to take load from an
> > existing node.
> > What I'm finding is that when I add a new node, (super)
> > column lookups begin failing (not sure if it was the row lookup failing
> or
> > the supercolumn lookup failing), and I'm not sure why.
>
> 1) You almost never actually want BOP.
> 2) You never want Cassandra to pick a token for you. IMO and the
> opinion of many others, the fact that it does this is a bug. Specify a
> token with initial_token.
> 3) You never want to use Supercolumns. The project does not support
> them but currently has no plan to deprecate them. Use composite row
> keys.
> 4) Unless your existing cluster consists of one node, you almost never
> want to add only a single new node to a cluster. In general you want
> to double it.
>
> In summary, you are Doing It just about as Wrong as possible... but on
> to your actual question ... ! :)
>
>
Well, at least I'm consistent :)  Thanks for the hints.  Unfortunately,
when I first brought up my system--with the goal of getting it up
quickly--I thought BOP and Supercolumns were the way to go.  Plus, the
small "cluster" of nodes I was using was on a hodgepodge of hardware.  I've
since had a chance to think somewhat about redesigning and rearchitecting,
but it seems like there's no "easy" way to convert it properly.  Step one
was to migrate everything over to a single dedicated node on reasonable
hardware, so I could begin the process, which brought me to the issue I
initially posted about.  But the problem is that this is a live system, so
data loss is an issue I'd like to avoid.


> In what way are the lookups "failing"? Is there an exception?
>
>
No exception--just failing in that the data should be there, but isn't.

Casey

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