On Thu, Jun 23, 2011 at 5:59 AM, Dominic Williams <dwilli...@system7.co.uk>wrote:
> Cassandra is a good system, but it has not reached version 1.0 yet, nor has > HBase etc. It is cutting edge technology and therefore in practice you are > unlikely to achieve five nines immediately - even if in theory with perfect > planning, perfect administration and so on, this should be achievable even > now. > Yep, this is a totally fair (and appreciated) point. > > The reasons you might choose Cassandra are:- > 1. New more flexible data model that may increase developer productivity > and lead to fast release cycle > Do you mean new to the developer? Or a new feature in Cassandra (e.g. something added to 0.8 for example)? > 2. Superior capability as concerns being able to *write* large volumes of > data, which is incredibly useful in many applications > Yep, this is obviously valuable for data crunching, analytics, reporting, etc. But how often is Cassandra used in 'read mostly' use cases? > 3. Horizontal scalability, where you can add nodes rather than buying > bigger machines > 4. Data redundancy, which means you have a kind of live backup going on a > bit like RAID - we use replication factor 3 for example > 5. Due to the redundancy of data across the cluster, the ability to perform > rolling restarts to administer and upgrade your nodes while the cluster > continues to run (yes, this is the feature that in theory allows for > continual operation, but in practice until we reach 1.0 I don't think five > nines of uptime is always possible in every scenario yet because of > deficiencies that may present themselves unexpectedly) > Is there a roadmap or time to 1.0? Even a ballpark time (e.g next year 3rd quarter, end of year, etc) would be great as it would help me understand where it may lie in relation to my production rollout. > 6. The benefit of building your new product on a platform designed to solve > many modern computing challenges that will give you a better upgrade path > e.g. for example in future when you grow you won't have to change over from > SQL to NoSQL because you're already on it! > Indeed, this is why we're evaluating Cassandra and a small number of others. To this end, how often to people use Cassandra today as their primary (only?) data store as a full replacement for MySQL/Oracle/Postgres? I understand there are many use cases to use Cassandra in special cases and in addition to a SQL data store. But is it used frequently enough as a total replacement? There's no right/wrong answer for me - I'm just trying to get a feel for the "we use it a lot for data mining and analytics and for 25% of our OLTP needs" vs "we use it for all of our app's primary needs". I'm just curious. Thoughts? Thanks! Les
