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 <ertio...@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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