There is a new DC-X virtual machine on our WebDAV Server. It replaces the existing virtual machine that is based on Debian 4.0.
Two thirds of our existing DC-X customers use Red Hat Enterprise Linux (the remaining installations use SUSE Enterprise Linux, Debian / Ubuntu is not being used on production systems afaik) – and there is a free and binary-compatible distribution called CentOS, that can be used and updated without support contracts.
The new VM is based on a 64-bit operating system as this is what all our customers use – nowadays, it does not make sense to set up 32-bit systems that can hardly make use of even 4 GB memory. This means that the virtual machine might not run on older PCs (3-4 years) as the CPU either does not have 64-Bit support or no 64-bit virtualization support.
Another important change is the MySQL version that is being used – MySQL 5.1 (the old Debian VM had MySQL 5.0). With MySQL 5.0 we had frequent deadlocks that impacted concurrent import processes. MySQL 5.1 is the minimal requirement for DC-X. MySQL 5.5 (just released under GA) will be evaluated during the next couple of weeks. The VM still has Oracle Instant Client configured in case you want to run it against an existing Oracle database.
You should assign at least 1 GB of memory to the VM for smooth operation. The filesystems (/ and /var/opt/) have 8 GB each, are configured with the Logical Volume Manager (lvm2) und and can be extended online (example at our wiki).
The installation protocol (that you might want to use to set up physical servers) can be found here.