subb wrote:
Yea, but isn't that the point? Using the resources I'm paying for?
We actually all benefit from the statistical sharing of resources (at least in terms of CPU and I/O - memory is guaranteed and fixed) beyond what you'd get if you equally divided up the host. Essentially you can get more than you pay for, but only when others aren't using it.
On a Linode 360 (oops, 512) there are roughly 40 Linodes on a single 8-processor host. Assuming a 2.5GHz processor (fairly typical host), that means that if everyone were using as much CPU as possible, we'd all get about 0.5GHz - probably closer to 0.4GHz if you take host usage into account. Nothing wrong with that per-se - it's about all we are guaranteed, but it'd be much slower than typical behavior.
In reality, we all tend to get far more than that (and can burst to a full 4 processors) because often many other nodes are idle at any given instant in time, and Linode doesn't limit us strictly to the portion of CPU that should be allocated to each Linode if evenly divided.
I/O is shared similarly in that there is some overall bandwidth available to the disk subsystem, and at any given moment it will be shared amongst all the Linode's performing I/O. So each Linode gets higher performance since on average many of the others are not doing I/O at the exact same instant.
That's still not to say that if you need the CPU or I/O you shouldn't just use it. It will be evenly shared amongst everyone on the same host who wants it at the same time, and that's what we all bought into when we selected our plan.
But running a completely CPU or I/O bound application constantly when not actually needed for your Linode's operation isn't quite "neighborly," as it will create contention that need not exist, and lower the processing power or I/O available to others. Heavy I/O is actually even worse than CPU as it's generally a more constrained resource.
We're all sort of in the same boat and have vested interests in using what we need, but not burning resources unnecessarily.
-- David