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The Late Spring Speaking Gauntlet

There are busy times for everyone and if you speak at conferences, the busy times are March,May and November. I am recovering from the early spring rush, and now it’s time to prepare for the late spring one.

I’ve been fortunate enough to be accepted to speak at the following regional SQL Saturdays and look forward to speaking and meeting new folks, along with catching up with conference friends:

Ansible tips’n’tricks: provision multiple machines in parallel with Vagrant and Ansible

Vagrant is a great tool that I’m regularly using for building playground environments on my laptop. I recently came across a slight inconvenience with Vagrant’s Virtualbox provider: occasionally I would like to spin up a Data Guard environment and provision both VMs in parallel to save time. Sadly you can’t bring up multiple machines in parallel using the VirtualBox provisioner according to the documentation . This was true as of April 11 2019 and might change in the future, so keep an eye out on the reference.

I very much prefer to save time by doing things in parallel, and so I started digging around how I could achieve this goal.

Ansible tips’n’tricks: testing and debugging Ansible scripts using Vagrant

At last year’s UKOUG I presented about Vagrant and how to use this great piece of software to test and debug Ansible scripts easily. Back then in December I promised a write-up, but for various reasons only now got around to finishing it.

Vagrant’s Ansible Provisioner

Vagrant offers two different Ansible provisioners: “ansible” and “ansible_local”. The “ansible” provisioner depends on a local Ansible installation, on the host. If this isn’t feasible, you can use “ansible_local” instead. As the name implies it executes code on the VM instead of on the host. This post is about the “ansible” provisioner.

Most people use Vagrant with the default VirtualBox provider, and so do I in this post.

dbca now makes it easy to configure OMF on file systems

Up until – and including – Oracle 12.1 I always found it not-quite-so-straight-forward to create a new database using Database Creation Assistant (dbca) and configure it with Oracle Managed Files (OMF) on a file system in silent mode. I really like to use OMF in my lab databases as it saves me a lot of typing. I have also seen Oracle databases deployed in the cloud on file systems without ASM. So I was quite happy to see the syntax for dbca -silent -createDatabase was extended.

This post has been written using Oracle 18.4.0 on Linux.

Getting locale warnings when logging on to Linux

This blogpost is about the reason and solving getting the following message, or messages alike these when logging i to a linux box using ssh:

-bash: warning: setlocale: LC_CTYPE: cannot change locale (UTF-8): No such file or directory

However, this is a warning. Please mind such an issue might be come up in another way, which can be more disrupting; at least in the past I had issues running perl for the same issue:

[root@dmcel01 ~]# /usr/local/bin/ipconf -verify
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = "en_US.UTF-8",
LC_ALL = "UTF-8",
LC_CTYPE = "UTF-8",
LANG = "en_US.UTF-8"
are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

/proc/meminfo formatted for humans

Here is a small awk script I use to format memory information on Linux:

Ansible tips’n’tricks: understanding your Ansible configuration

When writing automation scripts I tend to use a local Ansible configuration file. This has certain advantages for me, such as including it in a version control system (VCS). It also is a valid option for developers without access to the global configuration file installed by the package manager. And more convenient to use than setting environment variables.

WARNING: There are some very important security considerations though, which you must be aware of before using a local configuration file.

Until now I haven’t spent a lot of time thinking about configuration variables and the order of precedence, but that is exactly what I’d like to do in this post.

Oracle Linux 7 and a new YUM configuration since January 2019

For quite some time I used to have a configuration file /etc/yum.repos.d/public-yum-ol7.repo managing my package sources in lab VMs. Today I noticed that this configuration file is deprecated, and has been replaced by a new model. This is explained in the Oracle Linux 7 administrator guide and a few other sources I totally missed. I thought I’d show you the full story in this post before I go and change all my Ansible scripts :)

State of play before

To repeat the scenario I just went through, I created a new machine, server3, based on the stock Oracle Linux 7.6 image. After its initial boot I log in to the console to perform a yum upgrade.

Building your own local Oracle Linux 7 Vagrant base box

I have been talking about Vagrant for a long time and use it extensively on my Ubuntu-powered laptop. I am using Oracle Linux 7.6 for most of my lab builds, and I like to have specific tools such as collectl, perf, and many others available when the VM boots. I als like to stay in control of things, especially when it comes to downloading otherwise unknown things from the Internet I decided to learn how to create a Vagrant box myself.

Making sense of direct path reads during primary key lookups

I recently made an interesting observation while monitoring database performance on an Oracle Enterprise Edition system. While looking at some ASH data (for which you must be licensed appropriately!) I came across direct path reads attributed to a select statement performing a primary key lookup. At first, this didn’t make much sense to me, but it’s actually intended behaviour and not a bug.

In this post I’m reproducing what I observed. I am using Oracle 18.4.0 for this experiment running on my Linux lab environment. The hardware uses 1s8c16t with 64 GB of memory.