A Reader Responds: Hyper-V vs.
VMware ESX Server
After reading Michael Otey’s “Virtualization
Shootout, Part 1” (June 2008, InstantDoc ID
98879), I’ve grown more interested in
Hyper-V. However, I’m still unclear about a
couple things:
1. Cost—When you compared the cost
of VMware ESX Server with that of Hyper-V,
did you include the cost of Microsoft System
Center Virtual Machine Manager (SCVMM)?
As the article mentions, you need SCVMM to
perform quick migrations. I believe a Virtual-
Center for VMware Server license is included
in the VMware Infrastructure 3 (VI3) Foundation
bundle.
2. Migrations/Vmotion—For enterprise
systems, VMware’s Vmotion technology is
a must-have. Obviously, Microsoft’s quick
migration isn’t live. But what exactly does
“quick migration” mean to an
administrator or end user?
3. Drivers—The article mentions
that ESX Server’s drivers are in
the hypervisor and that Hyper-V’s
drivers are in the guest OS. What
are the repercussions for VM migrations?
In VI3, because the drivers
are in the hypervisor, the guest OS
receives generic drivers that are
“portable” across the infrastructure.
Typically, the only concern with
migrating VMs in VI3 is ensuring
that your CPUs contain the same feature set.
However, even if the CPUs are different and
support different features, the VMs can still
be migrated cold and brought up on the dissimilar
hardware with no problems.
Thank you for your help with these questions.
I look forward to further articles about
Hyper-V in the coming months.
—Brent McCraney
The cost comparison doesn’t include the cost
of SCVMM, which is required for quick migrations.
Likewise, it doesn’t include the cost of
VirtualCenter for VMware Server on the ESX
Server side. VirtualCenter is included in the
high-end editions of the VI management platform.
However, it isn’t included in the low-end
VI3 Foundation edition, which we used in our
comparison.
VMotion is certainly useful for unplanned
downtimes. But it isn’t necessary for most VM
implementations. VMotion permits the movement
of VMs between hosts without shutting
down the VM. You’ll experience a delay in
responsiveness while the VM movement takes
place. But when the process is done, the VM is
in the same state that it was prior to the move.
By contrast, Microsoft’s Quick Migration saves
the state of a VM before the move, making the
VM temporarily unavailable. Then, the system
moves the VM and
restores the state. A
brief interruption of
service occurs during
the move. But the
process is far quicker
than shutting down
and restarting the VM.
The location of the
drivers in the parent
partition doesn’t affect
the ability to migrate
VMs between Hyper-V
servers. Hyper-V VMs are completely portable,
just as ESX Server VMs are.
—Michael Otey
Setting Up a Cisco Router
I enjoyed Michael Dragone’s article, “9 Steps
to Setting Up a Cisco Router” (June 2008,
InstantDoc ID 98740). I have a quick question
about Listing 1’s extended access list 101. I
don’t think you need the first line: permit udp any eq bootps any eq bootpc. I think the third
line—permit udp any any—is a superset of
the first line and more than covers for it.
—Dimitrios Kalemis
You’re correct. The third line of access list 101
would account for line 1 and, in fact, make
it redundant. Most environments probably
wouldn’t need it; I have it in mine only so that
I can receive a public routable IP address from
my ISP. In addition, I have some Deny statements
in my access lists that make it a requirement
to have line 1 present. I apologize for any
confusion the code caused.
—Michael Dragone
Microsoft Responds:
Hyper-V vs. VMware ESX Server
According to the development schedule
specified in “Virtualization Shootout,
Part 2” (July 2008, InstantDoc ID 99248),
Microsoft’s Hyper-V was tested using
prereleased beta code. The performance
data in the review may not represent an
apples-to-apples comparison because all
the performance optimization occurs at
the very end of the development cycle.
Microsoft customers and partners
are seeing great cost savings and performance
results within their datacenters.
Most recently, QLogic published a benchmark
for I/O throughput for storage
devices going through Windows Server
2008 Hyper-V. At 180,000 I/Os per second
on a system running Hyper-V, virtual
machine connections are just 10 percent
shy of native performance. This benchmark
demonstrates Hyper-V’s ability to
bring the advantages of virtualization
to the most demanding datacenter. For
more information about installing and
testing Hyper-V, please check out the tuning
guide at www.microsoft.com/whdc/system/sysperf/Perf_tun_srv.mspx.
—Microsoft
We’re performing another round of tests
with production code and will publish the
results later this year.
—Amy Eisenberg
End of Article
