> On Sun, Jan 16, 2011 at 7:22 AM, Javier Guerra Giraldez <javier@xxxxxxxxxxx
>> On Sun, Jan 16, 2011 at 1:39 AM, Grant McWilliams
>> > As long as I use an LVM volume I get very very near real performance ie.
>> > mysqlbench comes in at about 99% of native.
>> without any real load on other DomUs, i guess
>> in my settings the biggest 'con' of virtualizing some loads is the
>> sharing of resources, not the hypervisor overhead. Since it's easier
>> (and cheaper) to get hardware oversized on CPU and RAM than on IO
>> speed (specially on IOPS), that means that i have some database
>> servers that I can't virtualize on the near term.
> But that is the same as just putting more than one service on one box. I
> believe he was wondering what the overhead was to virtualizing as apposed to
> bare metal. Anytime you have more than one process running on a box you have
> to think about the resources they use and how they'll interact with each
> other. This has nothing to do with virtualizing itself unless the hypervisor
> has a bad scheduler.
>> Of course, most of this would be solved by dedicating spindles instead
>> of LVs to VMs; maybe when (if?) i get most boxes with lots of 2.5"
>> bays, instead of the current 3.5" ones. Not using LVM is a real
>> drawback, but it still seems to be better than dedicating whole boxes.
> I've moved all my VMs to running on LVs on SSDs for this purpose. The
> overhead of LV over just bare drives is very very little unless you're doing
> a lot of snapshots.
> Grant McWilliams
> Some people, when confronted with a problem, think "I know, I'll use
> Now they have two problems.