JDPFu.com 2025

Below is the 3rd of 6 questions from a reader. I definitely don’t have all the answers, but I’m not short on opinions. ;)

Previous articles:
Part 1 – LVM+JFS+RAID | Part 2 – Service Virtualization | Part 3 – Virtualizing Media Storage | Part 4 – Hosting Email

duijf asks:

Q3: I intent (sic) to provide quite a lot of media to my internal network, if I choose for virtualisation, will the VMs be able to access the disk space outside of the container? I do not want to create TB size containers (or should I?). I will probably use the SMB protocol here.

Below is the 2nd of 6 questions from a reader. I definitely don’t have all the answers, but I’m not short on opinion. ;)

Part 1 – LVM+JFS+RAID | Part 2 – Service Virtualization | Part 3 – Virtualizing Media Storage | Part 4 – Hosting Email

duijf asks:

Q2: I read everywhere about Virtualisation, should I directly install packages to the base system to provide services, or should I virtualise all services? What are the advantages here?

Advantages of Virtualization

The list of advantages is long, but with those advantages comes a few disadvantages. I cannot hope to point out all the advantages, so I’ll limit it to just the main ones.

Sometime on Monday the database that we run our blog software on became corrupted to the point that accessing the blog wasn’t possible for hours, perhaps many, many hours.

I don’t know how long the error existed, just that I created a few new articles in the morning and didn’t check back until late afternoon to see the process eating 99.99% of the available CPU AND not serving any pages.

This weekend, my 3 yr old VirtualBox VDI storage for this, my primary virtual machine, was getting close to 100% filled. It was a 10G partition that started out as a 6.06 installation, then was upgraded to 8.04 and finally to 32-bit Ubuntu Server running 10.04. To get a GUI, I added LXDE a few minutes after the 10.04 upgrade about a year ago. So as I wanted to start a new development project leveraging PerlBrew to manage different versions of entire Perl versions, libraries and CPAN modules, I knew the little space remaining would not be enough.

I did a little research before I began. The web pages that I found seemed to be taking the long way around to solve a fairly easy issue. They wanted users to download some tool, which was completely unnecessary. Anyway, below the shortest, easiest, way to increase the available storage in a VDI-based virtual machine.

Below is the first of 6 questions from a reader. I definitely don’t have all the answers, but I’m not short on opinion. ;)

Part 1 – LVM+JFS+RAID | Part 2 – Service Virtualization | Part 3 – Virtualizing Media Storage | Part 4 – Hosting Email

duijf asks:

I have a total of 5 quiet 5400RPM 1TB drives configured in a RAID5+1 array. I installed Ubuntu Server 10.04 onto LVM , inside the LVs JFS is used as the file-system. Is this good practice?

We know intuitively that desktops are faster than laptops – well, most of us know that, but how much faster? I’ve written that video transcoding is 2-3x faster on a desktop than a laptop. Here’s another example where the laptop is slower than a common desktop. You should be able to reproduce this yourself.

I have used Thunderbird for at least 8 yrs and used Mozilla Mail built into Mozilla/Netscape before that. When the company started using Zimbra for email, IM, calendaring, Lightning never quite worked correctly. With v5 of Thunderbird, the integration to Zimbra with Lightning is working well. After using it about 2 months, I haven’t seen any failures – even on complex calendar settings.

Thunderbird v5 + Lightning Installation Steps

These instructions are for Ubuntu, but probably work with other distros too.

sudo add-apt-repository ppa:mozillateam/thunderbird-stable
sudo apt-get update
sudo apt-get install thunderbird  xul-ext-lightning

Sometimes I lose track of all the devices on a network and need a reminder of everything that is there. Under IPv6, you won’t scan the entire subnet – it would take millions of years – but under IPv4, you still use a scan. nmap is good for this and running it with operating system finger printing goes quickly (relatively speaking).

nmap OS finger print command

$ sudo nmap -O 192.168.0.0/24

Bare with me here. This is a great technique. I think you’ll thank me later after doing what this article suggests.

Homes and businesses today have lots of network devices. Using DHCP is the easiest way to get those on the network, but if you ever want those different devices to talk to each other, perhaps to transfer a file or to have a central backup server, then now your are running a network. Running a network means you probably want to know which devices are on your network or maybe that is just me. Perhaps you want each device to locate each other device too? Static IPs are possible under DHCP, sometimes called DHCP Reservations or Static Leases.

Make it easy for everyone in the house by using your router to force static IPs for the devices when they are at home, but still can connect to DHCP networks easily when roaming. This is really good for portable WiFi devices like laptops, smartphones, and for home entertainment devices that easily support DHCP.

Linux/Ubuntu (maybe others) – ssh key-based authentication made easier.

You know that you shouldn’t be using passwords to remotely connect to a different machine, but setting up key-based authentication has always been just a little too much hassle to bother. It really is simple, but there’s a tool to make it even easier. ssh-copy-id is included with Ubuntu-based distros (and probably others) to push the public key from your desktop to a server and append that public key to the end of the ~/.ssh/authorized_keys file.