Investigating the full table direct path / buffered decision.

A lot of blogposts and other internet publications have been written on the full segment scan behaviour of a serial process starting from Oracle version 11gR2. This behaviour is the Oracle engine making a decision between scanning the blocks of a segment into the Oracle buffercache or scanning these blocks into the process’ private process global area (PGA). This decision is even more important on the Exadata platform, because the Oracle engine must have made (more...) post upgrade step fails on Exadata storage software

I’ve done several Exadata deployments in the past two months and had to upgrade the Exadata storage software on half of them. Reason for that was because units shipped before May had their Exadata storage software version of

The upgrade process of the database nodes ran fine but when I ran -c for completing post upgrade steps I got an error that the system wasn’t on the expected (more...)

A Deep Dive into ASM redundancy in Exadata

I made this presentation at Serbia Oracle User Group event in Zlatibor and Harmony 2015 event in Tallinn at last month. Both were very nice organizations that i really enjoyed, learned much and met with many Oracle experts. I prepared this presentation to answer to following questions, which i think are really important for Exadata Database Machine administrators: - To what degree, disk and

How do I change DNS servers on Exadata storage servers

This is just a quick post to highlight a problem I had recently on another Exadata deployment.

For the most customers the management network on Exadata is routable and the DNS servers are accessible. However in a recent deployment for a financial organization this wasn’t the case and the storage servers were NOT able to reach the DNS servers. The customer provided a different set of DNS servers within the management network which were still (more...)

How to configure Power Distribution Units on Exadata X5

I’ve done several Exadata deployments recently and I have to say of all the components PDUs were hardest to configure. Important to notice that unlike earlier generations of Exadata the PDUs in X5 are Ehnanced PDUs and not Standard.

Reading the public documentation (Configuring the Power Distribution Units) it says that on PDUs with three power input leads you need to connect the middle power lead to the power source. Well I’ve done (more...)

IO Resource Manager for Pluggable Databases in Exadata

Another interesting topic that goes over and above the CDB Resource Manager Plans I described earlier this week is the implementation of IORM Plans for Pluggable Databases. Pluggable Databases are an interesting object for studies, and I like to research things. When 12c came out there was no support for offloading initially, it is required that you are on cell software 12.1.x.x.x for full 12c support on Exadata. One aspect I was particularly (more...)

Testing 12c CDB Resource Plans and a little bit about OEM Express

Inspired by Sue Lee’s presentation at Enkitec’s E4 conference I decided to re-run my test suite to work out how you can use Database and I/O Resource Manager in Oracle to help consolidating databases in the new Multi-Tenant architecture. I should point out briefly that the use of Multi-Tenant as demonstrated in this article requires you to have a license. Tuning tools shown will also require you to be appropriately (more...) fails with Unable to locate any IB switches

With the release of Exadata X5 Oracle introduced elastic configurations and changed the process on how the initial configuration is performed. Back before you had to run which would go across the nodes and change all the settings according to your config. This script has now evolved and it’s called which is part of OEDA (onecommand). During one of the recent deployments I ran into the below problem:

[root@node8 linux-x64]# ./applyElasticConfig. (more...)

How to configure Link Aggregation Control Protocol on Exadata

During a recent X5 installation I had to configure Link Aggregation Control Protocol (LACP) on the client network of the compute nodes. Although the ports were running at 10Gbits and default configuration of Active/Passive works perfectly fine the customer wanted even distribution of traffic and workload across their core switches.

Link Aggregation Control Protocol (LACP), also known as 802.3ad is a methods of combining multiple physical network connections into one logical connection to increase (more...)

#C15LV Collaborate’15 updates!!

Hi All, Last week, I registered my presence at Collaborate’15 in Las Vegas as a speaker, attendee and at Oracle demo booth duty. It was an awesome experience meeting some polished brains and smart minds. After the first day of registration, I attended the #DBIM12c session by Maria Colgan, #DB12c Multitenant by John McHugh and #Exadata session … Continue reading

Exadata Storage Index Min/Max Optimization

Before discussing the Exadata-specific feature, let’s review what the database engine can do independently of whether Exadata is used. To execute queries containing the min or max functions efficiently, two specific operations are available with B-tree indexes defined on the column referenced in the min or max function. The first, INDEX FULL SCAN (MIN/MAX), is used when a query doesn’t specify a range condition. In spite of its name, however, it performs no full (more...)

Exadata Documentation Available

Please join me in welcoming the Exadata product documentation to the internet. It’s been a long time coming, but glad it’s finally made an appearance!

Exadata 12c New Features RMOUG Slides

I've finally gotten around to post my RMOUG Slide Deck on Slideshare. Hopefully this is helpful to folks looking at new features in Exadata.

Exadata & In-Memory Real World Performance Artikel (German)

Heute wurde auf "" ein aktueller Artikel von mir veröffentlicht. Es geht darin um die Analyse eines Falles bei einem meiner Kunden, der auf Exadata nicht die erwartete Performance erreicht hat.

In dem Artikel werden unterschiedliche Abfrage-Profile analysiert und erklärt, wie diese unterschiedlichen Profile die speziellen Features von Exadata und In-Memory beeinflussen.

Teil 1 des Artikels
Teil 2 des Artikels

Want to learn Exadata ?

Many people have asked me this question that how they can learn Exadata ? It starts sounding even more difficult as a lot of people don’t have access to Exadata environments. So thought about writing a small post on the same.

It actually is not as difficult as it sounds. There are a lot of really good resources available from where you can learn about Exadata architecture and the things that work differently from any non-Exadata (more...)

Oracle Bundle Patching

I’ve spent a few days playing with patching with the so called “Database Patch for Engineered Systems and Database In-Memory”. Lets skip over why these not necessarily related feature sets should be bundled together into effectively a Bundle Patch.

First I was testing going from to BP2 or Then as soon as I’d done that of course BP3 was released.

So (more...)

UKOUG Tech14 slides – Exadata Security Best Practices

I think 2 years is long enough to wait between posts!

Today I delivered a session about Oracle Exadata Database Machine Best Practices and promised to post the slides for it (though no one asked about them :). I’ve also posted them to the Tech14 agenda as well.

Direct download: UKOUG Tech14 Exadata Security slides

The Importance of the In-Memory DUPLICATE Clause for a RAC System

With the INMEMORY clause you can specify 4 sub-clauses:

  • The MEMCOMPRESS clause specifies whether and how compression is used
  • The PRIORITY clause specifies the priority (“order”) in which the segments are loaded when the IMCS is populated
  • The DISTRIBUTE clause specifies how data is distributed across RAC instances
  • The DUPLICATE clause specifies whether and how data is duplicated across RAC instances

The aim of this post is not to describe these attribues in detail. Instead, (more...)

Exadata Shellshock: IB Switches Vulnerable

Andy Colvin has the lowdown on the Oracle response and fixes for the bash shellshock vulnerability.

However, when I last looked it seemed Oracle had not discussed anything regarding the IB switches being vulnerable.

The IB switches have bash running on them and Oracle have verified the IB switches are indeed vulnerable.

[root@dm01dbadm01 ~]# ssh

root@'s password:

Last login: Tue Sep 30 22:46:41 2014 from


Exadata and Bash Shellshock

There has recently been a lot of news about the exploit revealed in the bash shell.  While the fix is very quick to implement, there are a couple of tricks that are required to install this update on an Exadata environment.  According to Oracle support note #1405320.1, Exadata storage server versions 11.2.3.x.x and 12.1.1.x.x are susceptible to the exploit.  On a typical Oracle Enterprise Linux, a simple (more...)