Really the issue is that virtual hosts can affect each other quite a bit on Rackspace compared to, say, AWS. If your server behaves poorly, Rackspace can and will shut it off. One of our non-critical servers ran out of memory, thrashed swap, and was shut down in pretty short order by Rackspace. Which is good, sort of, I don't want to hurt other customers. Still, getting it turned back on was not a very fast process.
So it is kind of a roll of the dice. Are the other customers on your hardware well behaved? Will they stay that way?
It is a trade-off, you get way better performance if the other virtual hosts on the box are quiet. But if you plan your capacity around those quiet periods you can be in for quite a shock once the hardware gets busy. I've run critical servers on hosts like this and it can be a headache.
So it is kind of a roll of the dice. Are the other customers on your hardware well behaved? Will they stay that way?
It is a trade-off, you get way better performance if the other virtual hosts on the box are quiet. But if you plan your capacity around those quiet periods you can be in for quite a shock once the hardware gets busy. I've run critical servers on hosts like this and it can be a headache.