Out of curiosity, how common is it to have this kind of chroot jail instead of just installing your own linux in a full VM? I've never looked at hosting, but whenever we talked about it at work it was either putting your own hardware in someone's rack, or getting a VM that you could install/backup remotely, and it acted like a full machine with a wimpy CPU.
Just to clarify, openvz is not *quite* a chroot jail…it has some fancy features giving it control and isolation that has advantages over the classic chroot jail…and I'm pretty sure openvz devs bristle at the comparison :)
I called it that because from my perspective it's practically the same thing, given that there's just one kernel in play for multiple instances.
OpenVZ is actually very common because it's pretty cheap, resource-wise and service-wise. It's typically the "low service tier" on vpses for the very reason that people tend to bump up against limitations more often than on other types of virtualization. The performance can also be pretty lame…not because of some fault of OpenVZ, but because the way memory is presented, you could easily be working mostly in the host OS's swap and not even know it…and this is probably pretty common when a bunch of vm's are sardined onto a host OS.
Xen is also pretty common, but pricier since hosts have to know what they're doing a little more than with OpenVZ, and it's harder for them to play resource games (like pretending to give you more ram than they actually do). It's not at all a chroot jail…you have your own kernel and stuff.
Both types of vm's act like you'd expect a vm to act for the most part. You can shut them down, install packages, etc…very much like a vmware guest. Except, of course, that OpenVZ kinda sucks in the way already described :)
I found the problem. Installing the mpm_worker_thread for Apache2 uninstalled phpmyadmin and a few critical mysql components, so I simply needed to reinstall them, restart mysql and Apache2 and then it fired right up.
EDIT: And for the record, the solution to my core dumping problem was to get a Xen-based server with Linode. Core dumps worked with a fresh install, no configuration needed. Quantact did have amazing support though, but unfortunately the Linode control panel is amazing compared to Quantact's, and they also offer more bang for the buck.