I recently was tasked to convert a couple physical servers to virtual machines.

The physical servers basically had 2x 500GB SSDs in a RAID1 configuration, and the total used space was around 40GB.

To optimize the storage for the virtual machines, I needed to resize the VMDK files accordingly. This process involves several steps to ensure data integrity and minimize downtime.

Here I document the steps I took to safely resize a VMDK file, without modifying the virtual machine description file (VMX).

So recently I was tasked to set up a Slurm cluster for bioinformatics workloads, and I thought it would be a good idea to share some notes about the installation and configuration process.

So in short, before we start, what is Slurm?

Slurm is an open-source, fault-tolerant, and highly scalable cluster management and job scheduling system for large and small Linux clusters. It is used by many of the world’s supercomputers and computer clusters.

I heard too many times a work colleague, or a third-party vendor telling me “there is something wrong on the network here”, or “This port isn’t open!”.

You can use websites to try to test for open ports, a quick Google search should yield you a couple good results, but sometimes that is not enough.

# The problem

Let’s suppose you followed my other post about restricting source address with iptables, in this case those random web tools won’t help you, so you use nmap!