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From Michael Dürgner <mich...@duergner.de>
Subject Re: Best strategy for adding new nodes to the cluster
Date Tue, 28 Sep 2010 05:37:29 GMT


Sent from my iPhone

On 27.09.2010, at 19:30, Marc Canaleta <mcanaleta@gmail.com> wrote:

> What do you mean by "running live"? I am also planning to use cassandra on EC2 using
small nodes. Small nodes have 1/4 cpu of the large ones, 1/4 cost, but I/O is more than 1/4
(amazon does not give explicit I/O numbers...), so I think 4 small instances should perform
better than 1 large one (and the cost is the same), am I wrong?

Based on results we saw and what you also find in different sources around the web, EC2 small
instances perform worse than 1/4 regarding IO performance.

> El 27 de septiembre de 2010 18:09:14 UTC+2, Jonathan Ellis <jbellis@gmail.com>
escribió:
> I strongly recommend not running live on Small nodes.  So in your case
> I would recommend starting up Large instances with raid0'd disks, shut
> down cassandra on the Small ones, rsync to the Large, and start up on
> Large.
> 
> On Mon, Sep 27, 2010 at 6:46 AM, Utku Can Topçu <utku@topcu.gen.tr> wrote:
> > Hi All,
> >
> > We're currently running a cassandra cluster with Replication Factor 3,
> > consisting of 4 nodes.
> >
> > The current situation is:
> >
> > - The nodes are all identical (AWS small instances)
> > - Data directory is in the partition (/mnt) which has 150G capacity and each
> > node has around 90 GB load, so 60 G free space per node is left.
> >
> > So adding a new node to the cluster will seem to cause problems for us. I
> > think the node which will stream the data to the new bootstrapping node,
> > will not have enough disk space for anticompacting its data.
> >
> > What should be the best practice for such scenarios?
> >
> > Regards,
> >
> > Utku
> >
> 
> 
> 
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com
> 

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