Step 1. Boot up a brand new, default Ubuntu 11.04 Server install
Step 2. Install Cassandra from Apache APT Respository (deb http://www.apache.org/dist/cassandra/debian 08x main)
Step 3. apt-get install cassandra, as soon as it cassandra starts it will freeze the machine
What's happening is that as soon as cassandra starts up it immediately sucks up 100% of CPU and starves the machine. This effectively bricks the box until you boot into single user mode and disable the cassandra init.d script.
Under htop, the CPU usage shows up as "system" cpu, not user.
The machine I'm testing this on is a Quad-Core Sandy Bridge w/ 16GB of Memory, so it's not a system resource issue. I've also tested this on completely different hardware (Dual 64-Bit Xeons & AMD X4) and it has the same effect.
Ubuntu 10.10 does not exhibit the same issue. I have only tested 0.8 and 0.8.1.
root@cassandra01:/# java -version
java version "1.6.0_22"
OpenJDK Runtime Environment (IcedTea6 1.10.2) (6b22-1.10.2-0ubuntu1~11.04.1)
OpenJDK 64-Bit Server VM (build 20.0-b11, mixed mode)
root@cassandra:/# uname -a
Linux cassandra01 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
Intel(R) Xeon(R) CPU E31270 @ 3.40GHz
MemTotal: 16459776 kB
MemFree: 14190708 kB