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From aaron morton <aa...@thelastpickle.com>
Subject Re: cassandra nodes with mixed hard disk sizes
Date Tue, 22 Mar 2011 04:09:21 GMT
1) You should use nodes with the same capacity (CPU, RAM, HDD), cassandra assumes they are
all equal. 

2) Not sure what exactly would happen. Am guessing either the node would shutdown or writes
would eventually block, probably the former. If the node was up read performance may suffer
(if there were more writes been sent in). If you really want to know more let me know and
I may find time to dig into it. 

Also a node is be responsible for storing it's token range and acting as a replica for other
token ranges. So reducing the token range may not have a dramatic affect on the storage requirements.

 
Hope that helps. 
Aaron

On 22 Mar 2011, at 09:50, Jonathan Colby wrote:

> 
> This is a two part question ...
> 
> 1. If you have cassandra nodes with different sized hard disks,  how do you deal with
assigning the token ring such that the nodes with larger disks get more data?   In other words,
given equally distributed token ranges, when the smaller disk nodes run out of space, the
larger disk nodes with still have unused capacity.    Or is installing a mixed hardware cluster
a no-no?
> 
> 2. What happens when a cassandra node runs out of disk space for its data files?  Does
it continue serving the data while not accepting new data?  Or does the node break and require
manual intervention?
> 
> This info has alluded me elsewhere.
> Jon


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