January 29, 2012, in category Certification comments No comments

Judy Katz, the Communcations Manager over at Prometric released a document named “The Top 10 IT Certification Myths. Addressing the top 10 Myths About IT Certification: A Counterpoint Position to Misinterpretation” (read here).  In case you aren’t aware, Prometric handles the IBM certifications and many other certifications for big name IT leaders. Let’s take a quick look at what she talks about here.

Myths:

Certifications are Vendor-centric

• While this is true, the negative outlook on this truth is unwarranted.  Most technologies are developed by specific vendors, and certain vendors are the best to oversee certification over the technology...

January 24, 2012, in category Certification comments No comments

Many of you may be curious on the formatting of the certifications.  I know I was.  The certification tests are offered throughout the world, many of them at small business colleges.  Based on my experience, this is what you can expect:

• Multiple choice
• Video recording
• Computer based
• Timed
• Given a scrap of paper for notes
• Cannot bring cell phone’s into room

If you go to the IBM website you will see that most tests are broken down into categories.  These breakdowns are very accurate as you also get a print out at the end of how you did in each category. If you aren’t strong in a subject, LEARN IT.  It won’t be like in highschool where the teacher says something might be on the exam and it isn’t.  Each category listed is in fact on the exam, with weighting how it is outlined.

January 17, 2012, in category Problem Determination comments One comment

Often times when a file system fills up you will see one of two things:

1. Because you have a well monitored system, you will get an email alert that a threshold has been reached and the file system is filling up
2. Users are screaming because their applications are breaking and files aren’t being saved…

Regardless of which is happening to you, first thing to do is figure out WHY the file systems are filling up.

Nine times out of ten you’ll see that users are putting files where they shouldn’t.  Storing files or logs in the /home directory, saving stuff to /tmp and not deleting it, these are things you’ll see everyday.  Here’s how to figure out what’s going on.

$ df -m -> display the free space, in megabytes, on all file systems

$ who -> always good to see who is on the lpar (if the problem ...

January 17, 2012, in category Problem Determination comments No comments

In AIX there are a number of ways to check up on who has touched your server.  If something has been done and you aren’t sure who has been poking around, this will help you figure out.

**NOTE: this is made much simpler by disabling root SSH capabilities.  If you have not done this, please not that it is recommended to disallow SSH directly for root user as this will mask who has been logging into the system (as well as cause other security holes)

$ who -> This will tell you who is currently logged into the system, from where and when they logged on

$ last -> This will give you a list of previous logins, the source and time, both in and out

$ who /etc/security/failedlogin -> List all of the failed logins with the same details as above

$ history -1000 -> If you use shared user ids, or y...

January 17, 2012, in category Certification comments One comment

System Availability (10%)

1. Identify resources used by Cluster Aware AIX
2. Configure dump devices and analyze output
3. Determine elements necessary to reduce single points of failure
4. Understand geographical logical volume manager (GLVM)
5. Maintain hardware (CEC/Blade Hardware), deferred or concurrent firmware, AMM firmware (for Power Blades), whether an adapter replacement or new installation.

Storage Management (21%)

1. Create and manage filesystems
2. Create and manage logical volumes
3. Create and manage volume groups
4. Manage physical and virtual devices
5. Manage storage devices (traditional disk, Solid State Drives, and tape) including redundancy

System and Network Security (4%)

1. Configure Role Based Access Control
2. Configure and Manage remote access

Partition Management (11%)

1. Configure and manage Lo...

January 17, 2012, in category General Maintenance comments No comments

Workload Partitions are a form of compacting down your environment into something more manageable and faster/easier to deploy or destroy.  The idea of a WPAR is that you can run the work of multiple LPARs within a single LPAR.  By creating an LPAR with WPAR capabilities, you can fill it with images running multiple instances of AIX workloads.

By consolidating your LPAR environment, you can create more easily manageable servers for environments with multiple development, sandbox and testing deployments.  Often times with the increase in virtualization, we treat LPARs as though they are disposable machines (which technically they are).  By creating a WPAR, you increase the ease of set up, tie up less physical resources, and keep your environment breadth steady...

January 16, 2012, in category AIX Commands comments No comments

vi /etc/inittab = BAD IDEA

We all know that vi (or any other text editor) can easily edit a text file such as the inittab.  We also know that nobody is perfect, and that mistakes do happen (escape characters, wrong formatting etc.)  The problem is, when editing the inittab, if you make an error in the wrong place, you can render the system unbootable.  This is because the inittab is an important part of the boot sequence for an lpar, and once the boot sequence get mucked up, bad things start to happen.

This guide will go over the correct ways to edit the inittab without the risk of breaking the lpar altogether. (The only way to recover from some inittab errors are to network boot and fix from there…)

lsitab -a -> list contents of the inittab

lsitab identifier -> find specified identi...

January 12, 2012, in category AIX Commands, Scripts comments No comments

Well, not really.  But I assume I’ll get lots of attention with that name alone.  When I thought about writing this it was for one very specific thing only.

Often times in a script I’ll want to strip output based on a delimiter or columns.  I found myself constantly fighting with IFS and trying to make sense of delimiters that don’t follow a common pattern.  My two ways of extracting columns from a file/variable are as follows:

echo $variable | cut -f 2 -d “:” –> (-f to select column, -d to select delimiter)

echo $variable | awk ‘{ print $2 }’

Believe it or not, for someone that started off with no formal shell training or anything, this took me awhile to figure out.  Cut has its ups and downs but I will say this, awk is without a doubt worth learning.  In its entirety.

Anyways, th...

January 11, 2012, in category AIX Commands comments No comments

If you moved to AIX from Linux, like I did, the one thing you will miss with KSH is the command recall and auto-complete that BASH offered.  Well you needn’t worry because KSH has these capabilities, you just have to spend some time familiarising yourself with the new techniques.

This tutorial will be heavily related the the Vi Tutorial.  I suggest if you need more help or explanations with this, please visit that post for further explanation.

When using KSH, you can select the default history editor type.  To do this we use the “set -o” command.

$ set -o vi -> use vi as your command history editor

$ set -o emacs -> use emacs as your command history editor

$ set -o gmacs -> use gmacs as your command history editor

This will in turn allow you to use vi to edit the line that you are c...

January 11, 2012, in category AIX Commands, Scripts comments No comments

In shell scripting, you may run into a constant battle with quotation marks.  Seems silly, but between the three types (double quotes-”, single quotes-’, backticks-`), I have run into numerous problems that perhaps I can save you from.
First off, when copying any scripts, commands or data from the internet, if you run into any problems with code that is said to be tested, check the quotation marks.  Often times browsers, web themes or even copying and pasting can result into a mish-mash of punctuation changes.

Secondly, when nesting quotes in a script or command, be sure you a) alternate quotation styles when nesting and b) ensure your order of end-quoting matches.

A quick overview of meta characters is below.

Remember, anything in double quotes may be read by the shell interpreter and ...