I
frequently run into clients that are wanting to run Oracle products
in their VMWare cluster. Since I generally deal with E-Business
Suite customers, I tend to take the position of "anything that
swallows machines whole should probably have a physical machine"
approach to production systems. However, I can see some distinct
advantages to virtualization, particularly when it comes to managing
numbers of non-production environments.
Unfortunately,
there is a lot of confusion out there as it relates to Oracle and
virtualization... particularly surrounding one of the most popular
virtualization solutions, VMWare. I'll try to provide my best
understanding of the issues here.
Are
Oracle products certified on VMWare?
The
short answer is, NO. But, that
really shouldn't be that much of a concern. Keep in mind that a
VMWare Virtual Machine is, technically, hardware. Oracle doesn't
tend to certify against hardware. And that's what that VMWare really
is, it's "virtual hardware". As such, it's really no
different than a particular model of Dell or HP ProLiant.
What
Oracle does
do is certify against a platform. A platform is the combination
of a particular version of an operating system (Solaris 10 vs.
Solaris 11, for example) and processor architecture (Sun SPARC vs.
Intel x86-32 or Intel x86-64). In the case of a deployment to
VMWare, your platform will be determined by the operating system that
you intend to run inside of the virtual machine. (For example, Red
Hat Enterprise Linux 4/5/6 for x86 or x86-64).
Are
Oracle products supported on VMWare?
Oracle's
official support position can be found in MOS Note 249212.1, copied
below (emphasis mine):
Support
Position for Oracle Products Running on VMWare Virtualized
Environments [ID 249212.1]
Purpose
---------
Explain
to customers how Oracle supports our products when running on VMware
Scope
& Application
----------------------
For
Customers running Oracle products on VMware virtualized environments.
No limitation on use or distribution.
Support
Status for VMware Virtualized Environments
--------------------------------------------------
Oracle
has not certified any of its products on VMware virtualized
environments. Oracle Support will assist customers running Oracle
products on VMware in the following manner: Oracle will only provide
support for issues that either are known to occur on the native OS,
or can be demonstrated not to be as a result of running on VMware.
If
a problem is a known Oracle issue, Oracle support will recommend the
appropriate solution on the native OS. If that solution does not
work in the VMware virtualized environment, the customer will be
referred to VMwar for support. When the customer can demonstrate
that the Oracle solution does not work when running on the native OS,
Oracle will resume support, including logging a bug with Oracle
Development for investigation if required.
If
the problem is determined not to be a known Oracle issue, we will
refer the customer to VMware for support. When the customer can
demonstrate that the issue occurs when running on the native OS,
Oracle will resume support, including logging a bug with Oracle
Development for investigation if required.
NOTE:
Oracle has not certified any of its products on VMware. For Oracle
RAC, Oracle will only accept Service Requests as described in this
note on Oracle RAC 11.2.0.2 and later releases.
In
my understanding of the actual way that the policy is applied, it's
really a matter of whether or not the support engineer suspects
VMWare to be the culprit. What I'm saying here is that, generally
speaking, the support engineer will work your issue the same way that
he/she would if you were on physical hardware. However, once that
engineer thinks that VMWare could be the cause of your problem, they
reserve the right to "punt" and say "call us back once
you've reproduced it on physical hardware".
Now,
VMWare, to their credit, has a policy that they call "Total
Ownership", where they will accept accountability for any
Oracle-related issues. You can read their official policy at the
link below.
It
is my understanding that, as part of the "Total Ownership"
policy, VMware will reproduce the problem on physical hardware for
the customer if Oracle decides that VMWare is the problem.
What
about Licensing?
Part
of the big problem I've always had with Oracle on VMWare is caused by
Oracle's per-CPU licensing policy. My original understanding was
that, if you have a total of 64 cores in your VMWare cluster, it
didn't matter if you were only using 8 cores for Oracle. Oracle
would tell you that you had to pay for 64 cores. The idea behind
this is that you could, potentially, resize the virtual machine to
suit certain needs. Maybe you need more horsepower during month end?
What
I've since learned is that Oracle has a policy document (below) that
talks about "soft" vs. "hard" partitioning.
What
I've described above would fall under the concept of "soft
partitioning". However, "hard partitioning"
methodologies allow for a different approach. VMWare has (naturally)
a nice document that explains their approach to implementing clusters
that are in compliance with Oracle's licensing requirements.
From
that document, pay particular attention to section 2.2. In that
section (specifically Scenario B), they discuss DRS Host Affinity
rules and VMWare CPU pinning. (emphasis mine)
2.2
Clusters: Fully Licensed Versus Partially Licensed Clusters
Scenario
B: Partially Licensed Clusters
When
a customer does not have enough Oracle application instances to
justify creating a dedicated cluster for those applications, only a
subset of the hosts in the cluster are licensed for the Oracle
application. In this situation, the customer must be careful to
restrict the movement of Oracle application instances and virtual
machines to only those hosts that are licensed to run the product.
In
this case, DRS Host Affinity
rules can be used to appropriately restrict the movement of virtual
machines within the cluster. DRS Host Affinity is a
vSphere feature that enables you to ensure that your Oracle
applications are restricted to move only between a subset of the
hosts—that is, not all hardware in the cluster is “available”
to the Oracle software. DRS Host Affinity is a clustering technology
and is not a mechanism for soft or hard partitioning of the servers.
As explained in section 2.1, using VMware CPU pinning to partially
license a host is not currently recognized by Oracle as a “hard
partitioning” mechanism that receives subsystem pricing. However,
once you have fully licensed the host, you have the right to design
your environment such that the Oracle workloads are free to run on
the licensed hosts inside the cluster. At present, Oracle does not
have any stated policy regarding clustering mechanisms or DRS Host
Affinity. Customers can easily maiatain records for compliance
purposes as explained in section 2.3.
The
advantages of this approach are similar to the advantages achieved
with a fully licensed cluster. Because customers are typically able
to increase the utilization of licensed processors, they reduce
license requirements. However, consolidation ratios tend to be lower,
because advanced vSphere features can be employed only on a smaller
subset of the hosts.
VMWare
CPU pinning is a feature that (in my understanding) would allow you
to say that a given VM would only use certain cores in a physical
host. So, if you have a single host with 16 cores, you can "pin"
a given VM to four of them. According to Oracle's partitioning
document (and VMWare's document), you would still be required to pay
for all 16 cores in the box. The basic logic here is that Oracle's
licensing policy is based on the number of cores in a physical
server. You can't license part of a box. Period. No exceptions.
On
the other hand, DRS Host Affinity, is a way to pin a virtual machine
to a given host (or collection of hosts) within a cluster. So, let's
say that you have ten (10) 8-core physical hosts (total of 80 cores) in
your VMWare cluster. Using DRS Host Affinity, youcould restrict your
Oracle VMs to a subset of those physical hosts. For example, if you
restricted your Oracle VMs to only five (5) of those physical hosts,
VMWare's contention is that you would only have to license 40 cores.
I
sould probably include the standard "IANAL" (I am not a
lawyer) disclaimer. I'm also not a VMWare administrator. What I am
is a DBA and an IT Geek. That's pretty much the limit of it.
Hopefully
this provides some clarity on the issue.
For
further reading on the subject, here are a couple of blog links that
I used in my research:
– James
