Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> writes:
> Picture this (and assume tools exist to help you measure
> and manage it): Each user is billed only for the resources
> they use, including RAM. RAM "optimization" can be controlled
> by the user via a menu (or slider bar for more granularity);
> at one extreme, RAM (and more specifically page cache) is
> aggressively reduced... but only if another VM is demanding
> it. On the other extreme, fixed maximum RAM is fully owned
> by the user, and it sits idle if not in use. The user
> can choose dynamically whether to pay more for fast responsiveness,
> or to pay less and surrender RAM if needed elsewhere, with
> some probability for slower responsiveness.
That sounds excelent for situations where I can quickly and cheaply
move a guest from one piece of physical hardware to another.
> Does that sound more attractive to an IAAS provider?
This is useful in some cases. Still not in mine; see, I can't afford
shared storage, so giving me free ram that may only be free for a
few minutes is of limited utility. Yeah, I can use it as shared disk
cache for extra heavy disk users, but it's still a more complex model
for the customer to understand, and I can't bring up more guests on that
host. I could give it to other people on the same host, but
I think that might be of limited utility, as I don't know how many
customers will be willing to pay for extra capacity if that extra
capacity is only sometimes available.
But then, I am experimenting with low-cost homebrew OpenSolaris NAS setups,
so if that works out, and I get a working live migration system together,
then this could be useful. Not as useful as, say, some mechanisim for live
or nearly live migration with local storage, but still useful.
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