Tag Archives: performance

Oracle listened, customers WIN! RAC supported on VMware

As I was flying home last night and downloading tweets before takeoff, I found out some amazing news. Ugh, not the time to have intermittent internet access! But eventually I got home, did the reading and confirmed the news.

Oracle RAC 11gR2 ( is now supported by Oracle under VMware.

You can read the updated My Oracle Support (MOS) announcement yourself in note 249212.1 which now states:

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 and later releases.

(Remember:  Certified is different than Supported .  Oracle doesn't certify hardware that isn't Oracle's own )

This is simply fantastic news.  I talked to an petroleum company in Houston earlier this year who wanted to virtualize their Oracle EBS system and move platforms from Sun Solaris to x86 architecture.  Their big concern was that they were using 8 SPARC Processors and they knew that 8 x86 CPUs is the limit for a virtual machine under VMware vSphere 4.1.  We discussed various steps they could take to ensure their environment would thrive under this limitation, but now it's a non-issue. In the event they need more computing power, they can implement Oracle RAC under vSphere and start up another RAC instance as necessary. 
I do need to point out that as of this moment, database is not certified or supported with Oracle Application (Oracle EBS) 11i or R12.  These certifications usually come out a few months after the initial database announcement (which was Sept 10th for  If you check out the blog of Steven Chan (a Senior Director in Oracle's Applications Technology Group - the group responsible for the Oracle E-Business Suite technology stack) and specifically these comments , you'll see that Steven wrote:

We haven't certified with Oracle E-Business Suite Release
11i yet.  This project is underway now. is the latest
certified database release for the E-Business Suite.
Oracle's Revenue Recognition rules prohibit us from discussing
certification and release dates, but you're welcome to monitor or
subscribe to this blog for updates, which I'll post as soon as soon as
they're available.

So database certification with EBS 11i and R12 is coming.My main client doesn't use RAC (our business can survive the downtime associated with a HA event and we aren't near the 8 CPU limitation of VMware vSphere 4.1), but knowing its an option can only give upper management even more confidence that virtualizing our entire Oracle environment under VMware vSphere was the right thing to do.

For those wanting more information on Oracle RAC under VMware vSphere, I'd suggest watching this Oracle virtualization webcast put on by Embarcadero and VMware a few weeks ago. I'd also highly recommend following VirtualTodd on Twitter.  Todd Muirhead was at Oracle OpenWorld in the VMware booth and presented some very interesting performance data from running RAC under VMware.  I can't find a link to the presentation, but you can follow Todd's postings and perhaps find his testing results at his blog on the VMware communities site .

Think of the possibilities of combined Oracle RAC and VMware vSphere:

o  Multiple RAC nodes on different vSphere hosts means no database downtime during a hardware failure.

o  Combining multiple RAC databases on same vSphere host to consolidate workloads but still segregate environments 

o  Much faster provisioning of new RAC nodes with vSphere virtual machine cloning and VMware VAAI (vStorage APIs for Array integration)

o ... and many more I still need to wrap my head around

Webinars of interest to Oracle Apps DBAs on RedHat Linux with VMware

So recently I’ve been getting notifications about a number of various interesting Webinars. Since they’re coming from all sorts of random sources, I’m sharing the links as a service to my readers.

I’m receiving no consideration or such from the companies mentioned, these are things I thought would be of interest to me, and perhaps my readers

Upcoming (all dates / times are based on Central US time zone)

Get The Facts: Oracle’s Unbreakable Enterprise Kernel for Linux Oct 26th 11am, put on by Oracle

EBS Workflow Purging – Best Practices Nov 10th 11am, put on by Oracle

How to use My Oracle Support for ATG issues Oct 27th 11am, put on by Oracle

E-Business Suite using a DB-Tier with RAC Oct 28th 11am, put on by Oracle

Top 10 Virtual Storage Mistakes Oct 28th 1pm, put on by Quest Software

On-Demand (already happened)

Oracle Virtualization Webcast put on by Embarcadero and VMware

RHCE Virtual Loopback: Unlocking the value of the Cloud put on by RedHat (pdf)

RHCE Virtual Loopback: Performance and Scalability RHEL5 -> RHEL6 put on by RedHat (pdf)

Managing Red Hat Enterprise Linux in an Increasingly Virtual World put on by RedHat

State of “Btrfs” File System for Linux put on by Oracle

Lower Your Storage Costs with Oracle Database 11g and Compression put on by Oracle

Linux Configuration and Diagnostic Tips & Tricks put on by Oracle

Feel free to share any other Seminars you think may be of use in the comments!

Oracle Advanced Compression Advisor

My main Oracle Applications Database has been growing steadily and is now around 270GB. In terms of databases this isn’t huge, but when you keep multiple development and test copies around on enterprise class storage, AND replicate it to your DR site, that can get expensive.

With Oracle 11g database, Oracle came out with two products to help manage space (and improve performance!) in your Oracle database – Oracle Advanced Compression and Oracle SecureFiles. Although both are for reducing disk usage, they are aimed at different areas of disk usage within an Oracle database.

SecureFiles is the next generation of storage for Oracle LOBs (Large OBjects). Oracle LOBs stored in the format before SecureFiles are said to be stored in BasicFiles. SecureFiles is aimed at attachments to the database – CLOBS (Character LOBs), BLOBs (Binary LOBs), and NCLOBs (multi-byte character LOBs). SecureFiles offers a number of benefits over BasicFiles. Two are relevant to reducing space usage – de-duplification and compression. SecureFiles is a free feature of Enterprise Edition and has no additional licensing costs. As a result, it’s the sort of low hanging fruit that should be of interest to any Oracle DBA out there – free improved performance and free reduced disk storage. What’s not to like? Because this feature is free, we’re actively testing with this in our environments and plan on rolling this out by end of year. I’ll post a much longer blog post with our space savings and details of converting data from BasicFiles to SecureFiles later.

Advanced Compression is aimed at table data – compressing the data stored in the tables. This not only saves space on the file system, but actually improves performance by reducing the amount of data that needs to be read from disk (reading data from disk is frequently the bottleneck with Oracle databases – which is why Oracle is so memory hungry and tries to cache much of the data it needs in the System Global Area (SGA)). Advanced Compression is a add-on feature to Enterprise Edition at a cost of $11,500 per x86 license (and remember it takes TWO x86 CORES to equal one x86 LICENSE) – and like everything Oracle, that is based on how many cores are in the box, not how many your database cpu_count is set to or VM (if you virtualize your Oracle database) utilizes.

With Oracle Enterprise Manager (OEM) 11g, one of the new features is a Compression Advisor. You can read about other reasons to upgrade to OEM 11g at this blog post on OEM 11g new features. When run against an Oracle 11gR2 database, this advisor will analyze your database objects, estimate the compression ratio you’ll achieve and even make recommendations on the best compression settings for your environment. Although my largest database is 11gR2, I have a variety of other database versions on those same physical hosts (gotta love virtualization!) that aren’t 11gR2 and hence don’t have the DBMS_COMPRESSION package.

Luckily, I stumbled across a standalone version on Oracle Technology Network. This standalone version will work with Oracle 9iR2 (9.2.0.X) through 11gR1 (11.1.0.X) and can give you the data you need to convince business areas to upgrade to 11g database.

One thing to be aware of with this script: it will create a temporary table of the compressed data so you may wish to reating a tablespace specifically for storing the temporary table and making that the default tablespace of the user executing the script. The temporary table gets dropped at the end.

Note: The example on the Oracle Technology Network link above is incorrect. It is using the DBMS_COMPRESSION package which is in 11gR2 Oracle database and NOT provided by this package. So if using an 11gR2 database, you use DBMS_COMPRESSION package, but if using a 9iR2 thru 11gR1 database, use the DBMS_COMP_ADVISOR package like in my example below

Here’s the output from running it against a database with a table OM_DATA in a schema called OO_MAIL. The table has 4.5 million rows and is 9.5 GB in size. (The product that uses this database requires Oracle 9iR2, for those wondering)

SQL> exec DBMS_COMP_ADVISOR.getratio(‘OO_MAIL’,’OM_DATA’,’OLTP’,25);

Sampling table: OO_MAIL.OM_DATA

Sampling percentage: 25%

Compression Type: OLTP

Estimated Compression Ratio: 1.62

PL/SQL procedure successfully completed.

I also ran this against my largest table in my Oracle Applications (11gR2) instance (INV.MTL_TRANSACTION_ACCOUNTS) – a 2.5GB table with 14 million rows:


Sampling percentage: 25%
Compression Type: OLTP
Estimated Compression Ratio: 2.57

So that works out to 3.64GB space I would save on the 9i database and 1.57GB in my 11gR2 database. A total of about 5GB saved. Every database (and the data it contains) is different, so run the numbers against your database to decide if Advanced Compression is worth it in your environment… and check out SecureFiles. It’s free.

Oracle internal cloud session updates from VMworld Day 1

This week I’m at VMware VMworld in San Francisco. Yesterday was day one of the event and the Oracle related highlight for me was session

EA7061 Creating an Internal Oracle Database Cloud Using vSphere by Jeff Browning of EMC.

I’ve been to Jeff’s sessions before and always found them entertaining and informative. Below are some of my thoughts from what was covered at the session.

The most striking informative graphic was an X-Y graph where the X axis was scalability and Y was availability. At the high end of both were Oracle RAC. At the low end of both was MS Access and MySQL. In the sweet spot was Oracle standard edition coupled with VMware vSphere HA clusters.

What does this say to the DBAs? What many of us already knew – not every workload is appropriate for being virtualized under VMware. If your system or the business it’s supporting cannot survive the downtime you’d have in the event of a host failure and subsequent HA restart, you should spend the $$ for Oracle RAC. However, Jeff pointed out that in his experience roughly 90% of systems can survive the downtime associated with a HA event – that’s 90% of the databases out there being good candidates for virtualizing Oracle under VMware vSphere.

One of Jeff’s great examples of why to virtualize was to reduce database sprawl. He cited a Fortune 100 company with 824 physically booted Oracle databases and they pay $228 Million a year to support those machines.

To reduce this sprawl, you’ve got two approaches – according to Jeff, Oracle’s preferred way is to use RAC and come up with one global instance where you can put all your various products. Unfortunately that just doesn’t strike me as realistic in any sort of large company. I run primarily Oracle’s own products and even they can’t run on the same database version in many cases. Oracle E-Business requires Oracle 10g or Oracle 11gR2. Yet Oracle Email Center requires an Oracle 9i database (which needs RedHat 4). A global RAC instance just doesn’t make sense.

The other approach is to virtualize the machines – now I’ve got a RedHat 4 32-bit OS machine running Oracle 9i database on the same hardware as a RedHat 5 64-bit OS running a 11gR2 database. There’s lots of cost savings on both Oracle licensing and reducing the amount of hardware that one can gain with this approach.

One thing I hadn’t really thought about that Jeff brought up with regards to VMware vSphere and Oracle is that the time to vMotion your Oracle database can be longer than with other types of virtual machines – sometimes taking as long as twenty minutes. The reason for this has to deal with how vMotion works – its basically copying the contents of RAM for that VM to another server and then copying over memory blocks that have changed since the first copy, over and over till the delta is very small. Oracle heavily uses memory for its SGA (System Global Area) and so for heavy transaction OLTP systems, vMotions can take a longer than expected time.

The final thing I want to share from Jeff’s presentation was the relevant performance of different protocols and file systems with regards to Oracle and VMware. On the NAS (NFS) storage side, Jeff assigned a value of 95% efficiency when accessing database datafiles via Oracle Direct NFS (DNFS) offering. Compare this to 65% efficiency running VMDKs over traditional NFS. That’s a huge performance difference. As a result, Jeff recommends just using this for a boot / OS disk and definitely not for your database files. On the SAN side, Jeff noted the best performance (100% relative efficiency) comes from using Oracle’s Automatic Storage Management (ASM) with VMWare Raw Disk Mapping (RDM) containers. Compare this with a 98% efficiency with ASM using VMware Virtual Machine Disk Format (VMDK) containers. This is another example of how the Oracle DBAs need to communicate with the VMware administrators when planning out their environment. Many times DBAs don’t even realize they’re running in a virtual environment, and you can’t expect a VMware admin to know about the performance benefits of Oracle DNFS or ASM.

Overall it was a great session and I’m definitely looking forward to applying what I learned to my environments when I get back home.