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From David Koblas <kob...@extra.com>
Subject Re: Overfull node
Date Mon, 10 May 2010 15:34:01 GMT
Sounds great, will give it a go.  However, just to make sure I 
understand getting the keyspace correct.

Lets say I've got:
     A -- Node before overfull node in keyspace order
     O -- Overfull node
     B -- Node after O in keyspace order
     N -- New empty node

I'm going to assume that I should make the following assignment:
     keyspace(N) = keyspace(A) + ( keyspace(O) - keyspace(A) ) / 2

Or did I miss something else about keyspace ranges?
Thanks


On 5/7/10 1:25 PM, Jonathan Ellis wrote:
> If you're using RackUnawareStrategy (the default replication strategy)
> then you can "bootstrap" manually fairly easily -- copy all the data
> (not system) sstables from an overfull machine to a new machine,
> assign the new one a token that gives it about half of the old node's
> range, then start it with autobootstrap OFF.  Then run cleanup on both
> new and old nodes to remove the part of the data that belongs to the
> other.
>
> The downside vs real bootstrap is you can't do this safely while
> writes are coming in to the original node.  You can reduce your
> read-only period by doing an intial scp, then doing a flush + rsync
> when you're ready to take it read only.
>
> (https://issues.apache.org/jira/browse/CASSANDRA-579 will make this
> problem obsolete for 0.7 but that doesn't help you on 0.6, of course.)
>
> On Fri, May 7, 2010 at 2:08 PM, David Koblas<koblas@extra.com>  wrote:
>    
>> I've got two (out of five) nodes on my cassandra ring that somehow got too
>> full (e.g. over 60% disk space utilization).  I've now gotten a few new
>> machines added to the ring, but evertime one of the overfull nodes attempts
>> to stream its data it runs out of diskspace...  I've tried half a dozen
>> different bad ideas of how to get things moving along a bit smoother, but am
>> at a total loss at this point.
>>
>> Is there any good tricks to get cassandra to not need 2x the disk space to
>> stream out, or is something else potentially going on that's causing me
>> problems?
>>
>> Thanks,
>>
>>      
>
>
>    

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