The biggest Pros would be Disaster Recovery, Hardware Refresh, licensing reduction, ease of setting up a Proof Of Concept/patch test enviornment. Imagine a hardware refresh that is as simple as a reboot. DR can become as simple as a cold boot or even a fully automated transition with no downtime depening on how you build your enviornment. I've actutually set up systems where for a DR test host admins with zero Oracle training have recovered Oracle database servers and Fusion middleware servers with the same wizard interface they use to recover their Windows servers.

The cons would be licensing increase & a small performance hit

yes, licensing is both a Pro and a Con, depending on how you build your virtual enviornement and which hypervisor you use.

Licensing is based around what Oracle considers to be a "Hard partition" for CPU resources
For Oracle VM, virtual CPUs are Hard Partitions. Each virtual CPU is a treated as a processor core, so check Oracle licensing for the current multiplier (I believe .25)

For VMware vSphere/ESX, any connection other than managment is considered one hard partition. So if you put two physical servers each with two phyical CPUs and running 8 core cpus in a vCenter cluster, all of the CPUs within that cluster are considered one hard partition and must be licened per the current Oracle licesing spec. For x86 commondity servers, this is .5, so this setup would require 2 (Servers) x 2 (CPUs each) x 8 (cores/CPU) x .50 = 16 Processors of licensing. Confused? check out this blog http://oraclestorageguy.typepad.com/oraclestorageguy/2010/05/oracle-license-costs-on-the-vmware-vsphere-platform.html

Amazon's EC2 cloud is recognized as hard partitioning with a .25 modifier for the virtual CPUs.

Citrix, MS, & RedHat all also have hypervisor products as well. Each hypervisor vendor is treated differently, so research it first. You could either save your self large amounts of money, or cost yourself even more. If you have lots of very lightly loaded VM's I'd recommend vSphere and run many virtual machines per phyiscal host. This works great for development enviornements that need to be reconfigured a lot or run at different patch levels. If you have a higher CPU load on your current systems, look at Oracle VM. Speaking from experience, when you set up your virtual enviornment, do not skimp on RAM. Almost all deploys will hit a memory ceiling before hitting a CPU/PIO/network ceiling.

That said : from a technical perspective. You're abstracting the hardware, specifically you're abstracting CPU, RAM, Physical I/O and networking (attached storage can be considered PIO for this discussion, even SANs running FCoE). Any abstraction comes with a performance loss at the gain of flexiblity. This is true for Java VMs, native pl/sql vs pl/sql vm, _any_ abstraction. The good news is typically these resources still run at least at 95% of physical iron. Some hypervisor systems can abstract certain server resources, but offer others up directly. As an example, in the case of Cisco UCS and VMWare vSphere, the virtual server can have it's own HBA directly "attached" to your SAN storage, bringing PIO up to nearly the same speed as physical servers. RAM in VMware is always fed through the hypervisor & it's enhancements which can have either a positive or negative effect on an Oracle DB depending on the kinds of applications being run. RAM for other hypervisors such as XenServer & Cisco UCS aren't guided through a hypervisor so RAM access is _technically_ faster (98% iron speed vs 97% sort of difference, exact impact varies on config & load!) Other than a few tricks like this, any of the major vendors will work, but the current differences between them are in managment and integration (with backups/SAN/etc) VMware is the most mature by a couple of years & has the best integration & managment. Citrix, Cisco, & MS have solid managment (Cisco has some really cool trick in UCS since they control the hardware as well). Oracle VM is, well, mostly a manual headache. Give them 18months & I'm sure we'll see some drastic improvments here.

I believe that Oracle is tilting the licensing field to try to steer people towards Oracle VM since it can't currently compete head to head in the enterprise with more mature products. I'd pick which one to go with based on 1) is it VMware? 2) is it already in use somewhere in the company with a good tech that can help design the complete system (backup integration can be a real headache! if someone else has already solved that headace, don't reinvent the wheel!) 3) what will it do to my licensing?

Go talk with your desktop group. Seriously. Virtual Desktops are _the_ hot topic & there is a massive push to virtualize the desktop using something like XenDesktop on Cisco UCS or Vmware View on vSphere. They may already have a plan in place. See how it works out & can it be expanded to suit your needs?

Tom:

Would you recommend running several small "production" Oracle 11g R2 databases on a Virutal Box running Red Hat Linux (using VMware)? Would it run like if you are actually running on non virtual Red Hat Linux machine.

One DBA told me Oracle support will not provide any help with issues encountered if oracle is running on VM machine. They want you to replicate the issue on non-VM machine first. Is this true?
Is this correct?

Hi Tom,

could you please point me to a site where oracle is officially stating that it is supporting single instances running in VMWare guests?

Up to now, the latest information from oracle was always, that oracle only supports its own virtualization and not VMWare (got that from an oracle consultant in Duesseldorf).

Many thanks in advance!

Support Position for Oracle Products Running on VMWare Virtualized Environments (Doc ID 249212.1)

It seems oracle has changed the VMware support recently.

http://www.vmware.com/solutions/partners/alliances/oracle-vmware-support.html

http://blogs.gartner.com/chris-wolf/2010/11/10/oracle-broadens-x86-virtualization-support-but-work-remains/

It also seems oracle will support RAC running on vmware

http://searchoracle.techtarget.com/news/2240024587/Oracle-will-now-support-Oracle-RAC-on-VMware?asrc=EM_NLN_12841745&track=NL-333&ad=797062

http://www.pcworld.com/businesscenter/article/210332/oracle_praised_for_switch_on_vmware_rac_support.html

Here is the official note. Oracle is not ceritified on VM ware and support is as described below.


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 VMware
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.

This is a big issue. We had an Oracle audit and because the database could be 'assigned' to a number of VM's in the configuration Oracle demanded each one be licensed. We had to remove them from VM's to avoid huge licase costs. Mr Ellison is in it for the money, after all.

Hi Tom,

Oracle VM 3.0 the latest is impressive. In OOW, after the announcement of Oracle public cloud, I did some research on this topic and have some question for you.

1. Why a pool of storage is not a good idea. A pool of storage at oracle level would be ASM with a lot of disks and all virtual instance can access it and a common storage pool would save Oracle a lot of work so why Oracle separate storage for each cloud or each data service.

2. During an architectural analysis, We came face to face with IBM DB2 9.7. Since 9.0 IBM is using a thread based model, with a few process and a huge process hosting all threads, its similar to Oracle on windows, which has a one process Oracle.exe and all the other thread run inside it.

with IBM DB2, The advantage they have is, they can create multiple instance without vitalization.

Will you elaborate, which approach is better, Oracle Process based model or IBM DB2 thread based model. What are pros and cons of each approach. IBM DB2 claims that they have minimized context switch and usage of memory. but they are not tell what problems this approach bring to DB2.

Your answer will enlightening many peoples.

I agree with DJB that licensing is a big issue. Oracle require every physical server in a VMware cluster to have Oracle licenses, and all with the same options, regardless of what actually runs on the server. For small sites, you can't (economically) run Oracle on one server of a cluster and use the other servers for other things because the other servers will require Oracle licences.

Oracle Australia are demanding license fees after an audit, not allowing de-clustering, despite having only one, single node, database bound to a single physical server.

So VMware is good for various reasons, but you probably need an Oracle cluster and a non-Oracle cluster. Single database sites have to pay for Oracle licenses for unused machines if they want a cluster. Multi-database sites get better value. Failover capacity has to be fully licensed if it is inside the cluster. If Production has options you don't want for other environments (e.g. active dataguard) you may want a production VM cluster and and a test/qa VM cluster so you don't have to pay for the unused option on the test/qa servers.

This is not described in Oracle's licensing documents, as far as I can find, but these are the rules they enforce. (Their partitioning-070609.pdf document explicitly applies to partitioning within a server, so logically doesn't apply to clusters, but 'VMware is soft partitioning' is a key phrase in licensing discussions with Oracle)

Hi Tom,

I am asking you this question, because we have DB2 sales team advocating that their thread based DB2 model is better than Oracle process based.

I have failed to understand why they adopted thread based model in DB2. When I asked them they replied that thread based model is more efficient, since it require less over head in context switching and require less memory. further they can run multiple instance on demand without visualization or with visualization

I dont see DB2 as innovators, they propagated share nothing architecture for years and in the end adopted share everything architecture like Oracle. They were the top criticizes when we purchase our exadata machine and again they proved wrong. Now our clients have three exadata machines and some other are in pipeline.

but I need some convincing arguments why IBM adopted thread model with DB2 and what's its pros and cons and I know none can guide me better than you.

thanks

<<<that is because you cannot hard partition VM ware, if you use virtualization that hard partitions - you license only what you need. >>

interesting! and I thought sofware partitioning can work like physical partitioning where you create multiple VMs and you can allocate for VM#1 20% CPU and 30% RAM of the total resources on the physical machine and it should not exceed it.

I originally thought VMware can be configured that way.

If the machine has 2 dual-core CPUs, i should be able to tell VMware to use 1 CPU only for VM#1.

If that is not true, the only benefit i see from VMware is ability to run multiple O/S on one physical machine and maximizing usage of the resources used on that machine instead of having 3-4 physical machines with wasteful resources.

of course you have single point of failure too. Physcial machine goes bad, all VMs go down with it.

From the licensing perspective, the point about VMware being soft partitioning is that you can change what share of a server a virtual machine gets without even a reboot. VMware ESX can also be configured move a virtual machine to a new server on the fly without a reboot. This obviously creates an opportunity to change thee arrangements between the peak load period and when the Oracle auditor comes. Oracle require all the physical servers in the VMware cluster to be fully licensed.

we are going for virtualization in our company for the IT section, and we are now in the discussion phase, so my question is : what question can be asked to the oracle engineer, regarding risks, licenses , disadvantages about oracle in virtualization

Tom:

Do you agree with the following points made by some about virtualization by some techies. I would like to see your honest opinion on these points about running oracle on RHEL VM machine running ESXi.

1) database don't run well on VM machines. There is also a timestamp accuracy issue with transactions running on VM.

2) You will lose considerable perfornamce running database on VM instead of physical machine.

with vmware setup you will use an emulated disk on a remote ISSCI export and latencies will be huge and the throughput less good than otherwise

3) There are more points of failure for a database running on VM.


4) oracle support does not provide for their product on vmware unless the issue is well-known on the gues OS and known not to be linked with vmware in any way.

5) Running database on a low-cost physical machine is much easier to maintain, and sure to perform much better than any vmware + awfully expensive SAN or NAS setup, not to mention the network equipment.

Tom:

It seems nowadays many system admins just eat a lot of bologna! I do not know how they get their information.


But concerning your statement,
<<No one uses the system clock for transaction tracking>>

I always use SYSDATE function for transactions. Is not that using system clock for date/timestamp?