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Date: Wed, 21 Apr 2010 11:48:14 -0700
From: Anthony Molinaro <anthonym@alumni.caltech.edu>
To: user@cassandra.apache.org
Subject: Re: Clarification on Ring operations in Cassandra 0.5.1
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On Wed, Apr 21, 2010 at 12:05:07PM -0500, Jonathan Ellis wrote:
> On Wed, Apr 21, 2010 at 11:31 AM, Anthony Molinaro
> <anthonym@alumni.caltech.edu> wrote:
> >
> > On Wed, Apr 21, 2010 at 11:08:19AM -0500, Jonathan Ellis wrote:
> >> Yes, that looks right, where "token really close" means "slightly less
> >> than" (more than would move it into a different node's range).
> >
> > Is it better to go slightly less than (say Token - 1), or slightly more than
> > the beginning of the range (PreviousTokenInRing + 1). �I was assuming the
> > latter in my earlier email, but you seem to be suggesting the former?
> 
> Right, the former.

So why is Token - 1 better?  Doesn't that result in more data movement
than PreviousTokenInRing + 1?

> > Right, I was mostly wondering if I could speed things up by scping the
> > sstables while the system was running (since they shouldn't be changing).
> > Then in quick succession removetoken and bootstrap with the old token.
> > Probably grasping at straws here :b
> 
> Nope, bootstrap ignores any local data.
> 
> You could use scp-then-repair if you can tolerate slightly out of date
> data being served by the new machine until the repair finishes.

So with scp-then-repair, what would my config look like?  Would I specify
the InitialToken as the same as the old token, but have AutoBootstrap
set to false?  I guess this is interesting to me because I could do something
where I migrate my data on a running server to an attached ebs, then
after it's synced, detach and re-attach to the new machine.

Anyway, thanks for discussing the possibilities,

-Anthony

-- 
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Anthony Molinaro                           <anthonym@alumni.caltech.edu>