Tutorial

Techstack n - 1 is dead!

TL;DR TechStack n-1 is dead. It ended with the rise of the clouds and software release cycles going down to weeks due to containerized CIs.

Against ‘it’s stable and mature so let it run’

The Death of Sophocles (Creative Commons)

Beeing OpenSource-based, Ubuntu already had the concept of point releases every 6 months when the Docker and K8s hit the world and gave automated CIs a big boost in making system containers. Some years after Docker itself switched to a 3-month release cycle. So did the Linux Kernel with 2-3 months. Firefox 4-weeks.

AWS sync is not reliable!

While migrating from s3cmd to the AWS S3 CLI, I noticed that files did not reliably sync when using the AWS CLI.

I tested this behavior with different versions, and they all exhibited the same issue:

python2.7-awscli1.9.7
python2.7-awscli1.15.47
python3.6-awscli1.15.47

Test Setup

Set up the AWS CLI utility and configure your credentials.
Create a testing S3 bucket.

Set up some random files:

# Create 10 random files of 10MB each
for i in {1..10}; do dd if=/dev/urandom of=multi/part-$i.out bs=1MB count=10; done;
# Then copy the first 5 files over
mkdir multi-changed
cp -r multi/part-{1,2,3,4,5}.out multi-changed
# And replace the content in the remaining 5 files (6-10)
for i in {6..10}; do dd if=/dev/urandom of=multi-changed/part-$i.out bs=1MB count=10; done;

Testing S3 sync with AWS CLI

Cleanup

$ aws s3 rm s3://l3testing/multi --recursive

Inital sync

$ aws s3 sync multi s3://l3testing/multi
upload: multi/part-1.out to s3://l3testing/multi/part-1.out       
upload: multi/part-3.out to s3://l3testing/multi/part-3.out     
upload: multi/part-2.out to s3://l3testing/multi/part-2.out     
upload: multi/part-4.out to s3://l3testing/multi/part-4.out     
upload: multi/part-10.out to s3://l3testing/multi/part-10.out   
upload: multi/part-5.out to s3://l3testing/multi/part-5.out     
upload: multi/part-6.out to s3://l3testing/multi/part-6.out     
upload: multi/part-8.out to s3://l3testing/multi/part-8.out     
upload: multi/part-7.out to s3://l3testing/multi/part-7.out     
upload: multi/part-9.out to s3://l3testing/multi/part-9.out

Update files

Only 5 files should now be uploaded. Timestamps for all 10 files should be changed.

Laptop Performance: irqbalancer vs. intel_pstate

Today I uninstalled irqbalancer and noticed a performance gain on my GNOME desktop.

The CPUfreq control panel showed me IRQBALANCE DETECTED, and they state the following:

Why I should not use a single core for power saving

Modern OS/kernels work better on multi-core architectures.

You need at least 1 core for a foreground application and 1 for background system services.

Linux Kernel switches between CPU cores to avoid overheating, CPU thermal throttling, and to balance system load.

Many CPUs have Hyper-Threading (HT) technology enabled by default. So there is no reason to run half of a physical CPU core.

These points are stated very simply. I feel there are some contradictions here.