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From Janne Jalkanen <Janne.Jalka...@ecyrd.com>
Subject Re: Which of these VPS configurations would perform better for Cassandra ?
Date Wed, 07 Aug 2013 06:24:57 GMT

Well, Amazon is expensive. Hetzner will sell you dedicated SSD RAID-1 servers with 32GB RAM
and 4 cores with HT for €59/mth.  However, if pricing is an issue, you could start with:

1 server : read at ONE, write at ONE, RF=1. You will have consistency, but not high availability.
This is the same as with MySQL or any other single-server solution - if the db server goes
down, your service goes down.  You will need to be extra careful with backups here, because
if your node blows, you will need to restore.

then you upgrade to

2 servers: read at ONE, write at ONE, RF=2. You can now tolerate one node going down with
automatic failover, but you won't get consistency.  This is kinda having MySQL master/slave
replication (yes, I know, it's not really the same, but it's pretty close as an effect)

then you upgrade to

3 servers: read at QUORUM, write at QUORUM, RF=3. You can tolerate one node going down, and
you will have consistent data. This is where Cassandra starts to shine.

then you get a big heap-o-money, and keep adding servers and you realize that with pretty
much everything else you would be spending a LOT of time just to keep sure that your cluster
is up and running and performing.

It's always a question of tradeoffs. Cassandra is cool 'cos it gives you the ability to run
a lot of different configurations and will go up-up-up when you need it without a lot of special
magic.

/Janne

On Aug 7, 2013, at 07:36 , Ertio Lew <ertiop93@gmail.com> wrote:

> Amazon seems to much overprice its services. If you look out for a similar size deployment
elsewhere like linode or digital ocean(very competitive pricing), you'll notice huge differences.
Ok, some services & features are extra but may we all don't need them necessarily &
when you can host on non-dedicated virtual servers on Amazon you can also do it with similar
configuration nodes elsewhere too.
> 
> IMO these huge costs associated with cassandra deployment are too heavy for small startups
just starting out. I believe, If you consider a deployment for similar application using MySQL
it should be quite cheaper/ affordable(though i'm not exactly sure). Atleast you don't usually
create a cluster from the beginning. Probably we made a wrong decision to choose cassandra
considering only its technological advantages.


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