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From aaron morton <>
Subject Re: nodetool move hammers the next node in the ring
Date Sat, 09 Apr 2011 02:35:33 GMT
My brain just started working. The streaming for the move may need to be throttled, but once
the file has been received the bloom filters, row indexes and secondary indexes are built.
That will also take some effort, do you have any secondary indexes? 

If you are doing a move again could you try turing up logging to DEBUG on one of the neighbour
nodes. Once the file has been received you will see a message saying "Finished {file_name}.
Sending ack to {remote_ip}". After this log message the rebuilds will start,  would be interesting
to see what is more heavy weight I'm guessing the rebuilds.

This is similar to but that ticket will
not cover this case. I've added this use case to the comments, please check there if you want
to follow along.


On 6 Apr 2011, at 16:26, Jonathan Colby wrote:

> thanks for the response Aaron.   Our cluster has 6 nodes with 10 GB load on each.   RF=3.
   AMD 64 bit Blades, Quad Core, 8 GB ram,  running Debian Linux.  Swap off.  Cassandra 0.7.4
> On Apr 6, 2011, at 2:40 AM, aaron morton wrote:
>> Not that I know of, may be useful to be able to throttle things. But if the receiving
node has little head room it may still be overwhelmed.
>> Currently there is a single thread for streaming. If we were to throttle it may be
best to make it multi threaded with a single concurrent stream per end point. 
>> Out of interest how many nodes do you have and whats the RF?
>> Aaron
>> On 6 Apr 2011, at 01:16, Jonathan Colby wrote:
>>> When doing a move, decommission, loadbalance, etc.  data is streamed to the next
node in such a way that it really strains the receiving node - to the point where it has a
problem serving requests.   
>>> Any way to throttle the streaming of data?

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