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https://issues.apache.org/jira/browse/KAFKA-188?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13467419#comment-13467419
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Jonathan Creasy edited comment on KAFKA-188 at 10/2/12 1:32 PM:
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Yes please, I have the code written, and I even tested it a little, but I've 
been able to spend no time on it in a few weeks. It's probably not done yet, 
but it's close.
                
      was (Author: jcreasy):
    Yes please, I have the code done, and I even tested it a little, but I've 
been able to spend no time on it in a few weeks. 
                  
> Support multiple data directories
> ---------------------------------
>
>                 Key: KAFKA-188
>                 URL: https://issues.apache.org/jira/browse/KAFKA-188
>             Project: Kafka
>          Issue Type: New Feature
>            Reporter: Jay Kreps
>
> Currently we allow only a single data directory. This means that a multi-disk 
> configuration needs to be a RAID array or LVM volume or something like that 
> to be mounted as a single directory.
> For a high-throughput low-reliability configuration this would mean RAID0 
> striping. Common wisdom in Hadoop land has it that a JBOD setup that just 
> mounts each disk as a separate directory and does application-level balancing 
> over these results in about 30% write-improvement. For example see this claim 
> here:
>   http://old.nabble.com/Re%3A-RAID-vs.-JBOD-p21466110.html
> It is not clear to me why this would be the case--it seems the RAID 
> controller should be able to balance writes as well as the application so it 
> may depend on the details of the setup.
> Nonetheless this would be really easy to implement, all you need to do is add 
> multiple data directories and balance partition creation over these disks.
> One problem this might cause is if a particular topic is much larger than the 
> others it might unbalance the load across the disks. The partition->disk 
> assignment policy should probably attempt to evenly spread each topic to 
> avoid this, rather than just trying keep the number of partitions balanced 
> between disks.

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