DB2 is incredibly underrated outside the "large enterprise" crowd. It is a truly awesome RDBMS with bazillions of cool features (and a somewhat ugly Java UI). It has the equivalents of most of Oracle's features and has the scalability of Oracle while being both more user-friendly and considerably cheaper.

Its response times for simple queries are not exactly stellar though so I wouldn't recommend it for simple CRUD websites. But for serious data heavyweighting on a budget, DB2 Express-C (the free edition) is excellent.

As much as looking a gift horse in the mouth is poor form, I can't resist doing it. In the download page, drilled down to the "Get Support and Extra Features" link: http://www-01.ibm.com/software/data/db2/express/support.html...

    [Feature                    Free      Paid (3k USD/yr)]
    ...
    Data replication            No        Yes
    Max. processor utilization	2 cores   4 cores (max 2 sockets)
    Max. memory utilization     2GB       4GB
    ...

As a chaser, I like to read Robert Young's opinions on DBs, such as http://drcoddwasright.blogspot.com/2009/04/what-i-told-bob.h...

On the limitations of the free DB2 Express-C. We did make a very conscious decision to make REAL DB2 available at no charge and not some crippled version like Microsoft and Oracle "Express" database offerings. Why? We wanted to create an opportunity for anyone regardless of their financial situation to be able to get the benefit of all of the DB2 features and be able to use it not just to learn but to actually use in real applications. This means that without paying IBM a cent, you can use DB2 in any and all of your projects. You can even redistribute DB2 as part of your application without paying any royalties to IBM. And, if you find yourself fortunate enough to have created a very popular piece of software that needs more resources (memory and CPU power) then all you need to do is replace the license and you now have more processing capacity. Think of it. No need to rewrite a single line of code; no need to even have access to source. Btw. the price to move up to more resources and full IBM 24x7 support is exactly the same as what you would pay for equivalent MySQL support option. http://freedb2.com/2008/03/13/free-db2-is-cheaper-than-mysql...

Robert Yong in his post tries to speculate and pontificate. One thing about speculation is that you will likely get things wrong. And he gets it wrong on every point. He does not have any insight in to what went in IBM. Take it from someone who does. Just because someone has a blog does not make him an expert.

(Late notes, mostly to jot down a few URLs; also, the R.Young post I linked to above got further debate)

- At http://news.ycombinator.com/item?id=1084150, late in 2009, there had been some debate on the merits/etc. of DB2.

- R.Young is giving the "DB2 9.7 freebie" a spin under Linux: http://drcoddwasright.blogspot.com/2010/06/bill-teds-excelle...

- A bit of search led to a series of articles by Chris Eaton. List at http://it.toolbox.com/blogs/db2luw, best practices to configure DB2 guides at http://it.toolbox.com/blogs/db2luw/best-practices-for-db2-fo...

- Another post in that series includes a comment which clarifies what is and is not included in DB2v9.7 Express-C: http://it.toolbox.com/blogs/db2luw/db2-97-announced-by-ibm-i... ["What is not yet included in Express-C is PL/SQL support, CLPplus or build in package libraries (DBMS_PIPE, UTL_SMTP, etc)."]

To be fair he did say you are getting the full version of DB2 not some neglected DB2-lite, so you have to expect some catch. The restrictions are basically saying DB2, free for small websites.

No catch. Unless you need more then 2gb ram and more then 2 cores.