My ISP recently gave me a free speed bump from 500Mbps to 1 Gbps. I wanted to test if it was possible to fully utilise the bandwidth on a single file transfer. Firstly, we need to look at the test file size. I settled on a roughly 500MB to 1GB file size to minimise the effect of TCP window size ...

A port can only be bound to one service at a time, which makes perfect sense since the OS cannot possibly know which application to route the packet to. However, protocols often have distinct signatures, for example the first few bytes of SSH is always SSH-2.0 while HTTP packets always start ...

A number of friends have recently sought my advice on NAS and RAID solutions for storing their personal data. I do not usually give brand recommendations but I will discuss the technology involved. I have never used RAID nor found a need for it, this is because RAID (Redundant Array of ...

I have using xenserver as my hypervisor for the past 6 months and have run a number of VMs on it. However, there were some deal breakers which led me to migrate back to running Ubuntu as the base OS and running the VMs in VirtualBox on top of Ubuntu. Lack of USB passthrough support - Can only ...

On the 6th of Mar, while performing routine maintenance on my server, bash commands suddenly stopped working. 1 2 3 4 $ pwd -bash: pwd: command not found $ ls -bash: ls: command not found At that point in time, apache web server was still running. I took the risk and asked for the server to be ...

I have recently started managing yet another server. The server is running Ubuntu 14.04 LTS and therefore support is good for another 5 years. Just to be safe, I double checked the openssl version after updating to make sure that it is not vulnerable to heartbleed. # openssl version OpenSSL ...

I am quite surprised to find that linux has quite poor support for rar files. I have tried both unrar-free as well as the non-free version but both fail spectacularly at decompressing password protected multi-part archives. A few seconds into decompressing, an error message pops up claiming the ...

Recently did quite a lot of mysql related administration. Found quite a few ways to optimise that may make future administration easier. 1) If you are going to add/drop databases very frequently, you might want to add innodb_file_per_table=1 into your my.cnf config file. This will allow mysql ...