Oracle’s ASM Filter Driver Revisited


Almost exactly a year ago I published a post covering my first impressions of the ASM Filter Driver (ASMFD) released in Oracle, followed swiftly by a second post showing that it didn’t work with 4k native devices.

When I wrote that first post I was about to start my summer holidays, so I’m afraid to admit that I was a little sloppy and made some false assumptions toward the end – assumptions (more...)

Log Buffer #433: A Carnival of the Vanities for DBAs

This Log Buffer Edition covers Oracle, SQL Server and MySQL blogs of the running week.


  • While checking the sources of the Cassandra/NetBeans integration into GitHub yesterday, something went very badly wrong and ALL the source files in my Maven project that disappeared!
  • AWR Reports, Performance Hub, historisches SQL Monitoring in 12c
  • Oracle Database Mobile Server 12c: Advanced data synchronization engine
  • ORA-39001, ORA-39000 and ORA-39142
  • ORA-15410: Disks in disk group do not (more...)

Introducing FETCHER in a running replication process

This is no regular bit of work and it will probably (and hopefully) never hit you in a production setup…

The prerequisite is that you know how on-line data replication in general, and Dbvisit Replicate specifically, work.

The following case is true:
I had half of a replication pair running.
It means that the MINE process was running, converting REDO-log in PLOG-format. The APPLY process had not yet started because the target database was (more...)

Oracle DBAs: Producing Patches

In an Oracle DBA’s life, you’ll be regularly asked to work on applying a new patchset on a database and then you will apply it starting from the development database to the production database and this process can be quite long depending on the organization you are working for.

In an Oracle DBA’s life, you’ll be regularly asked to refresh a development database (or any environment before the production) with the production data for development, test or whatever needs. For (more...)

Use DB Vault to protect password strength policy

Suppose your organization wants to enforce a security policy on database password strength. The DBA’s have implemented a password strength verification function in PLSQL such as the oracle supplied ora12c_strong_verify_function in the DEFAULT profile of the database. There seems no way to get around it at first:

Database account u4 is created:




U4 logs in and tries to keep it simple, i.e. the password:




That password verification function got in (more...)

Error referenced ‘irman ioracle’ during binary installation

This week I decided to redo a few of my virtual box machines and build a few new ones for testing. Getting the Oracle Linux 6.6 installed was a breeze; however, when I started to install the Oracle Database 12c binaries I was hitting errors during the linking phase. This had me puzzled for a bit to say the least. I kept getting this error:

After driving myself nuts, I decided to look closer (more...)

Query existing HBase tables with SQL using Apache Phoenix

Spending a bit more time with Apache Phoenix in my previous post I realised that you can use it to query existing HBase tables. That is NOT tables created using Apache Phoenix, but HBase - the columnar NoSQL database in Hadoop.

I think this is cool as it gives you the ability to use SQL on an HBase table.

To test this, let's say you login to HBase and you create an HBase table like (more...)

HAIP and Exadata

If you’ve run an exachk report, y0u may have seen the following message with regard to your databases:

Status Type Message Status On Details
FAIL Database Check Database parameter CLUSTER_INTERCONNECTS is NOT set to the recommended value db01:dbm011, db02:dbm012 View

This check is commonly seen when a database is created on Exadata without using the custom “Exadata” templates included with the database creation assistant.  These customized templates include a multitude of recommended parameter settings found in (more...)

Kscope15, a celebration of tech…

Kscope15 promised to be a brand new experience in more than one way.

Kscope15LogoAs I start to write this report, I am flying from Düsseldorf airport to Atlanta. It will be the first time flying to the United States with a stopover, and because of Erik van Roon, I came prepared. With just carry-on luggage, I should end up at my final destination, Fort Lauderdale, Florida, together with my ‘stuff’. I am flying Delta (more...)

Key take-aways from the Oracle PaaS Cloud announcements – Integrate, Accelerate, Lead

imageMonday June 22nd was the launch date for Oracle for 24 (and more) Cloud Services. June is traditionally an important month for Oracle when it comes to product launches and important announcements. This year is the same in that respect. The announcements came in a many-hour live webcast including a 45 minute presentation by Oracle CTO Larry Ellison (see videos from Oracle Cloud Platform Launch). I have harvested some of the most relevant slides (more...)

Security Features of Standard Edition (One) – Part 2


Some Musings on the Security Implications of Oracle Database Initialization Parameters

Still following the steps of a database installation, this article will muse about some Initialization Parameters with security relevance.
In order to make a Standard Edition database as secure as possible we could start by looking what is the same in SE and EE, which are in their basic security functions more or less equal (security targets of 11g for EE and (more...)

Using a terminal emulator on Mac

Dumb title for a blog post? No, not really I guess…

ZOC Terminal emulatorI have been using a terminal emulator, basically ever since I got away from the VT100 terminal:

  • ICE.TCP Pro
  • Reflection ‘X’

And a few other obscure applications that I cannot even recall anymore.
Currently, and over the last 6 to 8 years, I have been using ZOC.

The background of this story is: In the beginning these were the first DOS PC’s (more...)

Register redo-log manually with Divisit Replicate

For those of you who haven’t been working with on-line data replication; in short, it is a way to copy data from a source database to a target database and do this on-line (both databases are active) and do it near-real-time.
This means that when you enter data in you source database, you can immediately query it from your target database. This makes on-line data replication ideal for numerous tasks, like moving and / or (more...)

Introduction to Oracle Database 12c

With the launch of DB 12c in 2013, Oracle introduced a new architectural concept, called “multitenant databases”, where you have one super database (=container; CDB) and one or more sub databases (= pluggable DBs; PDB).

Before running the installer on an Oracle Linux 6 environment, a library can be installed through yum to meet all the system per-requisites:

yum install oracle-rdbms-server-12cR1-preinstall

The software installer and DBCA are similar to 11g, except for this screen where (more...)

The Great Hypervisor Bake-off: VMware ESX vs Oracle VM


This is a very simple post to show the results of some recent testing that Tom and I ran using Oracle SLOB on Violin to determine the impact of using virtualization. But before we get to that, I am duty bound to write a paragraph of text featuring lots of long sentences peppered with industry buzz words. Forgive me, it’s just the way I’m wired.

It is increasingly common these days to find database environments running (more...)

Re-Adding a Database to the AWR Warehouse Without Losing Historical Snapshots

There may be a reason that one needs to re-add a database to the AWR Warehouse.  This is a new opportunity for me to learn and offer assistance, but I’m working off the grid to figure out a solution.  Luckily, it’s just a matter of creating a new process from pre-existing code and processes.

The process requires both the AWR Warehouse UI and a SQLPlus connection.

1.  Disable the snapshots

2.  Extract the AWR for (more...)

ASM Rebalance Too Slow? 3 Tips To Improve Rebalance Times


I’ve run into a few customers recently who have had problems with their ASM rebalance operations running too slowly. Surprisingly, there were some simple concepts being overlooked – and once these were understood, the rebalance times were dramatically improved. For that reason, I’m documenting the solutions here… I hope that somebody, somewhere benefits…

1. Don’t Overbalance

Every time you run an ALTER DISKGROUP <NAME> REBALANCE operation you initiate a large amount of I/O workload as (more...)

DBAKevlar at Collaborate 2015

Here’s a quick guide to my schedule of sessions at IOUG Collaborate 2015 for this year.  I’m looking forward to seeing everyone next week, (I’ll be arriving on Saturday, so I really should say in a couple days) and have no doubt we’re up for another phenomenal conference at Las Vegas, this year at the Mandalay!

Additionally, there are some great opportunities in professional development at the IOUG Strategic Leadership Program.  I’ll be speaking with James (more...)

IOUG Collaborate 2015 – #C15LV

Like many other Oracle professionals and speakers I will be attending IOUG Collaborate 2015 this year in Las Vegas.  I’m not a big fan of Las Vegas, but hey cannot turn down an opportunity to speak, especially when IOUG asked me to do more than one session.  

This year my schedule is going to keep me busy; yet full of good topics that cover both EM12c and GoldenGate.  If you are going to be (more...)

Paris Oracle Meetup (Jeudi 26 Mars 2015 @ 7pm)

A quick post to say that this week, on Thursday 26th, I will be giving a talk (in English!) on the subject of Flash for DBAs (and architects, designers, developers, managers etc) at the Paris Oracle Meetup:

global_197134042Flash for DBAs: A new technology is sweeping the world of storage. Flash, a type of non-volatile memory, is gradually replacing hard disk drives. It began in consumer electronic devices such as phones, cameras and tablets (more...)