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From Eric Czech <e...@nextbigsound.com>
Subject Re: unwanted node discovery
Date Mon, 03 Oct 2011 17:14:26 GMT
The tokens were different than the production cluster and after closer
inspection a lot of data wasn't queryable (as excpected I suppose).  I set
the tokens and everything seems ok now.

Auto bootstrap was false so no issues there.

Thanks for the insight Shyamal!  It's good to finally have this up and
running.


On Sun, Oct 2, 2011 at 8:29 PM, Shyamal Prasad <shyamal@member.fsf.org>wrote:

> >>>>> "Eric" == Eric Czech <eric@nextbigsound.com> writes:
>
>     Eric> Yea that's not a mapping I'd like to maintain either -- as an
>    Eric> experiment, I copied production sstables to the analysis
>    Eric> cluster and ran brisk/cassandra without specifying an initial
>    Eric> token (after deleting the LocationInfo* files and renaming the
>    Eric> cluster).
>
> Based on my understanding this will allow everything to start up, yes.
>
>    Eric>  As far as I can tell, everything is running normally but I'm
>    Eric> not sure how the cluster chose tokens for the nodes given that
>    Eric> I didn't specify them after just dropping the raw sstables
>    Eric> in.  I can still read data as usual from the column families
>    Eric> that were copied but I'm not sure how not specifying the
>    Eric> tokens affects everything.
>
> Did you check the ring to see what tokens you got for the analysis
> cluster? I would be surprised if you got the same ring configuration as
> production.
>
>    Eric>  Is some of my data just unreachable now because the tokens
>    Eric> weren't manually defined?
>
> I suspect your data is messed up. But the best way to determine it would
> be to examine the ring (use nodetool) - if it is the same as your
> production cluster you are good to go.
>
> Also, did you set your (non seed) nodes in the analysis cluster to auto
> bootstrap or not? That impacts what happens.
>
>
>    Eric>  This doesn't appear to be the case but is this something you
>    Eric> have tried too or do you understand the storage / topology
>    Eric> logic well enough to know that this isn't a viable strategy?
>
> No and No. I have been reading the code. Line 497 of
> org.apache.cassandra.service.StorageService.java on trunk is a good
> place to start since what happens depends somewhat on your specific
> cassandra.yaml settings (specifically auto bootstrap).
>
> I would be betting you are getting random tokens (look for "Generated
> random token..." in your log). Don't trust me, read the code. I have all
> of two weeks of experience with this stuff (and it's not quite my day
> job to be doing it either :-)
>
> Bottom line: I think you need to fix the seeds for your use case.
>
> Cheers!
> Shyamal
>

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