Even now I wouldn't recommend using Debian (Squeeze) as OpenVZ Host. We had some serious problems;
- CPU limits don't work. This was a known upstream OpenVZ-bug which was later on fixed, but this fix could not easily be backported to the (near vanilla) 2.6.32 Debian kernel, since OpenVZ-upstream only developes for the (far from vanilla) 2.6.32 RedHat kernel. (And Redhat does not release seperate patches anymore). IoW: in fact hardly any OpenVZ-upstream fixes can flow into Debian right now, so I would prefer if Debian would officially state that they cannot support OpenVZ anymore right now not only for wheezy.
- Occasionally one guest would rum amok and only a reboot of the *host* would help. It was "fun" moving all the other guests to different hosts.
Even though we use only debian for everything else, it was decided to switch all the OpenVZ-hosts to Sientific Linux. This switch ist not quite complete yet, but a colleague said: "Now OpenVZ is fun again".