[Info-vax] VMware

[Craig A. Berry]

On 12/10/19 12:38 PM, Grant Taylor wrote:
> On 12/10/19 8:14 AM, Craig A. Berry wrote:
>> Doesn't being able to do that depend on OS capabilities that quiesce 
>> everything while the running instance is being moved?
> 
> Nope.
> 
> The hypervisor does it transparently.
> 
> The guest VMs that have no idea that they are being moved any more than 
> a physical box knows that it's being scooted across the floor while it's 
> running with long network & power cords.

So there is a perfect up-to-date mirror in hard real time of all of the
states of all of the devices and all these different states are
coordinated with each other? For example, if I'm in the middle of
changing my password when one of these transitions happens, the state of
this process on the new instance looks exactly like it was on the old
one regardless of whether the I/O is in a network buffer, heap memory,
file system buffer, on disk, or split among some combination of two or
more of the above?

If that's true it sounds impressive.  But if the hypervisors are that
good it makes me wonder why Microsoft needed to spend megabucks on
making SQL Server and Windows work better under hypervisors (and I
believe similar efforts have gone into Linux).