Migrating My WordPress Blog to a New Server

I was using my ODROID-XU4 CloudShell to run my WordPress blog (the blog site which your are reading now) and other services. It is speedy and fulfills the role well. The one thing I am annoyed about is the noise of the fan when it comes on. It gets to the point that I can no longer work in that room when the fan comes on. I have to do something. I happen to have several ODROID-U3s lying around since I replaced my ODROID-U3 cluster with my ODROID C2 cluster. The ODROID-U3 has a heat sink and no fan. I can run my WordPress blog on a SD card instead of a hard disk like that of the CloudShell. This article describes my journey in migrating my WordPress blog from the CloudShell to the ODROID-U3. I also created a replica for testing/backup on another fanless server using docker. I shall cover that in this article as well. Continue reading Migrating My WordPress Blog to a New Server

Home Compute Cluster Revamp – Part 1

Introduction

High Performance Computing or HPC refers to the practice of aggregating computing power in a way that delivers much higher performance than one could get out of a single machine in order to solve large problems in science, engineering, or business. In the past, it was quite costly to build a HPC cluster. But with the ever diminishing cost of hardware, I built one some months ago for experimentation. It is now due for a revamp. But before I describe the revamp details, here is a recap on the existing HPC cluster which I shall refer to as my home Compute Cluster. Continue reading Home Compute Cluster Revamp – Part 1

Defending Hacking Attacks on My Home Server

After putting my home server online running my blog and other applications accessible from the Internet, I left it unattended for a few days and then I found that I couldn’t access my blog from the Internet any more. It has been attacked by hackers using Denial-of-service attacks. Hackers created a large number of half-open TCP connections to the server and established connections to the Apache Web Server. The latter caused the Apache Web Server’s Prefork Multi-Processing Module (MPM) to spawn the maximum number of Processes allowed. This combination brought the server performance to a stand-still. The DMZ I created appears to be holding up as I did not find any evidence on hackers breaking through my second firewall. Continue reading Defending Hacking Attacks on My Home Server

Using Odroid XU4 CloudShell as My Home Server

For those who are not familiar with Odroid XU4 and CloudShell, Odroid XU4 is an ARM-based Octa core single board computer based on the Samsung Exynos5422 2Ghz Cortex A15 and Cortex A7 cores with 2 Gbytes of memory. CloudShell is a compact case for Odroid XU4 with a 2.2 inch TFT LCD and a USB 3 to SATA bridge for connection to a 2.5 inch SATA hard disk. The assembled CloudShell is shown in the diagram below.

The ARM big.LITTLE technology is ideal for a home server in that when the cpu load is low, it uses the power efficient A7 core(s) and when the load is high, it switches to use the high performance A15 core(s). It may use 1 core, more than 1 core or all cores at the same time depending on the load. This means energy saving in the long run.

This article is not an Odroid XU4 review. For that you can read this in-depth review here. This article describes my experience in using this wonderful little device. Continue reading Using Odroid XU4 CloudShell as My Home Server