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From Ryan King <r...@twitter.com>
Subject Re: Can Cassandra make real use of several DataFileDirectories?
Date Mon, 26 Apr 2010 16:53:10 GMT
I would recommend using RAID-0 rather that multiple data directories.

-ryan

2010/4/26 Roland Hänel <roland@haenel.me>:
> I have a configuration like this:
>
>   <DataFileDirectories>
>       <DataFileDirectory>/storage01/cassandra/data</DataFileDirectory>
>       <DataFileDirectory>/storage02/cassandra/data</DataFileDirectory>
>       <DataFileDirectory>/storage03/cassandra/data</DataFileDirectory>
>   </DataFileDirectories>
>
> After loading a big chunk of data into cassandra, I end up wich some 70GB in
> the first directory, and only about 10GB in the second and third one. All
> rows are quite small, so it's not just some big rows that contain the
> majority of data.
>
> Does Cassandra have the ability to 'see' the maximum available space in
> these directory? I'm asking myself this question since my limit is 100GB,
> and the first directory is approaching this limit...
>
> And, wouldn't it be better if Cassandra tried to 'load-balance' the files
> inside the directories because this will result in better (read) performance
> if the directories are on different disks (which is the case for me)?
>
> Any help is appreciated.
>
> Roland
>
>

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