Hi, The idea behind Cassandra is not the same as for MySQL. First of all you can't get fault tolerance with one node. I don't think Cassandra nodes are more prone to be unavailable, but by using replication you can get more availability right away. If you have multiple instances when you start out, you have the right configuration when things get too large for one node. Then there is the issue that Cassandra is often used with very large data or very high traffic, to which it scales very well. If you don't expect to ever scale beyond one node (because traffic will never be high, you will never have much data or you never need the extra availability) then you of course could use one single node without lots of RAM, but it _could_ also be that *SQL is a better option? If you are a startup with great plans but no money and not much data/traffic (yet:), or just want to test Cassandra, then I still would suggest >1 nodes (3?), and instead reduce RAM and/or CPU to get the right price. In that case you could try to use Tomcat on one of the nodes. This way you can see and test what Cassandra does really well. It is not really that Cassandra demands more than other databases, but more that the problems it is designed to solve demands more than some other problems. FYI, I use 2-3 nodes with 2gb RAM each for testing, and have never had any problems with that. .vegard, ----- Original Message ----- From: user@cassandra.apache.org To:"user" Cc: Sent:Wed, 18 Sep 2013 19:04:27 +0530 Subject:Why don't you start off with a “single & small” Cassandra server as you usually do it with MySQL?
For any website just starting out, the load initially is minimal & grows with a slow pace initially. People usually start with their MySQL based sites with a single server(***that too a VPS not a dedicated server) running as both app server as well as DB server & usually get too far with this setup & only as they feel the need they separate the DB from the app server giving it a separate VPS server. This is what a start up expects the things to be while planning about resources procurement. But so far what I have seen, it's something very different with Cassandra. People usually recommend starting out with atleast a 3 node cluster, (on dedicated servers) with lots & lots of RAM. 4GB or 8GB RAM is what they suggest to start with. So is it that Cassandra requires more hardware resources in comparison to MySQL, for a website to deliver similar performance, serve similar load/ traffic & same amount of data. I understand about higher storage requirements of Cassandra due to replication but what about other hardware resources ? Can't we start off with Cassandra based apps just like MySQL. Starting with 1 or 2 VPS & adding more whenever there's a need ? I don't want to compare apples with oranges. I just want to know how much more dangerous situation I may be in when I start out with a single node VPS based cassandra installation Vs a single node VPS based MySQL installation. Difference between these two situations. Are cassandra servers more prone to be unavailable than MySQL servers ? What is bad if I put tomcat too along with Cassandra as people use LAMP stack on single server. --------- _This question is also posted at StackOverflow here [1] & has an open bounty worth +50 rep._ Links: ------ [1] http://stackoverflow.com/questions/18462530/why-dont-you-start-off-with-a-single-small-cassandra-server-as-you-usually