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From aaron morton <aa...@thelastpickle.com>
Subject Re: SSTable symlinks
Date Mon, 13 Feb 2012 19:43:43 GMT
> I am nursing an overloaded 0.6 cluster
Shine on you crazy diamond.

If you have some additional storage available I would:

1) Allocate a data directory for each node, stop the node and add the directory to the config
for each node in the DataFileDirectory
  <DataFileDirectories>
      <DataFileDirectory>/var/lib/cassandra/data</DataFileDirectory>
  </DataFileDirectories>

2) The nodes will now create SSTables in the new directory. Bring it back up and compact.


3) Once you have compacted I would recommend stopping the node, moving the SSTables back to
the local node and removing the additional data file directory. 

Hope that helps.


-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 14/02/2012, at 7:10 AM, Dan Retzlaff wrote:

> Hi all,
> 
> I am nursing an overloaded 0.6 cluster through compaction to get its disk usage under
50%. Many rows' content have been replaced so that after compaction there will be plenty of
room, but a couple of nodes are currently at 95%.
> 
> One strategy I considered is temporarily moving a couple of the larger SSTables to an
NFS mount and putting symlinks in the data directory. However, Jonathan says that Cassandra
is not okay with symlinked SSTables [1]. Can someone elaborate on why this won't work?
> 
> If a hack like this is not possible, then I am at a loss for options other than ungracefully
dropping the node from the cluster and reconstructing its data from other replicas. If anyone
has recovered from a similar situation, I would appreciate your advice.
> 
> Regards,
> Dan
> 
> [1] http://mail-archives.apache.org/mod_mbox/cassandra-user/201106.mbox/%3CBANLkTina%2BtZf9BhQwzW0Fnv-KAL7%2BKZArQ%40mail.gmail.com%3E
> 
> 


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