Adding new hdisks to a VIOS

I have a customer where they have an AIX 7.1 environment served by a NetApp providing storage. We use these hdisks as backing devices (disks) to serve LPARs we provision for their private cloud.

The configuration is fairly typical, the NetApp exposes storage via iSCSI LUNs to the VIOS.

The Virtual I/O Server is a software appliance that enables the sharing of physical resources among multiple logical partitions (LPARs). These physical resources are typically network and disk.

So once the LUNs have been created on the NetApp head (iSCSI target) and mapped to the VIOS (iSCSI initiator), we can do a hardware discovery to bring them in.

Log in to the VIOS as padmin

# ssh -l padmin VIOS_HOSTNAME
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Replace multiple instances of a file with find

I needed to replace a file that existed in multiple locations on my system with a new copy.

At first I considered a for loop in bash to do it, but then it occurred to me that find would be an ideal fit for this.

To search and replace a file(s) with find, go to the directory you want to search under and use the following command:

find . -name FILENAME -exec cp -f /PATH_AND_NAME_OF_NEWFILE {} \;

That’s it.

This handy little command will search out all instances of FILENAME under your current location and replace them with the new file.

Oh and if  you are using Windows, you can do the same thing with the find included with cygwin.

You ARE running cygwin, aren’t you? If not, then give it a shot. 🙂

Source and Destination Network Address Translation (SNAT / DNAT) with iptables

A colleague of mine approached me with a need to do some IP address translation.

He had a machine (A) with an IP of and he wanted any connections coming to this machine to get rerouted to another machine (B) with an IP address of

Machine A was a linux system and was the default gateway for machine B (*). This was a perfect fit for a  SNAT/DNAT using iptables.

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Extending a root filesystem in Linux without LVM


One of the great things about working with virtual environments is that if you start to run out of space in a virtual machine, it is usually trivial to extend your disk. I’m going to take the example of a Linux guest under VMware Workstation though this should apply to most hypervisors and flavors of Linux.

If your VM is not using LVM, the steps you’ll perform are:

  1. Extend the size of the physical disk
  2. Extend the size of the partition on the physical disk
  3. Do an online resize of the filesystem to use the new space Read more of this post

A natural progression

I’ve been working with systems and networking for over a decade and a half  and I’ve had the good fortune of having had the opportunity to work with telcos, internet service providers, banks, governments and multinational industry giants. My experience ranges from networking at the physical layer and working on telco wiring closets at remote satellite stations to network load balancing at regional datacenters, from hardening of financial systems to disaster recovery planning, from the automated deployment of virtual images on different hypervisors to attaching storage area networks to clusters of hypervisors.

I’m starting this blog as a vehicle for two goals:

  1. To share my knowledge with those who could benefit from it
  2. To build a network of people I know who trust me and want to work with me

For me, this blog is a natural progression from maintaining connections through and email.

I hope you find useful information here. If you have any questions, feel free to reach out to me through comments here.