The anatomy of a WordPress theme

My cousin asked me to develop a website for her Father's business. Initially I thought this would be a great learning experience as I knew the basics of web development (HTML, CSS, PHP, and a bit of JavaScript) but had never completed a full website before. I slowly but surely realised just what I had landed myself into... !

To cut a long story short I decided it would be best to implement a WordPress theme! I've always heard this makes content management very straightforward and doesn't require much knowledge of PHP / HTML for managing. Sounds perfect - Unless you're the one developing the site in which case it's a fucking balls.

Had I known how difficult this would be I definitely would not have chosen WordPress for my first development job. I guess the first hurdle I encountered was understanding the template hierarchy. See what I did at first was simply hard code an index.php and styles.css and upload them as a theme. Then I tried to create a new page from within WordPress and that wouldn't work - It kept bringing me back to index.php. I had also tried to create a contact.php with the company contact details - Now how the hell do I open this in WordPress? Hmmmm.. !

It was at this point I learned about the WordPress Theme Hierarchy. I didn't understand it, but I knew it existed. So I kept trying numerous different implementations, none of which worked. Read multiple blog posts and just ended up confused. Until I saw the 'template-loader.php' being mentioned somewhere and this is what finally made me understand the theme template. Show me in code and I'll understand!

Let's take a look:

Examining this file is what finally made everything click with me in terms of how pages get selected, and the reason why creating a new page in the WordPress GUI was not working. I only had an index.php! Basically, this code steps through each of the query context conditionals in a specific order, and defines the template to use for the first one that returns true. So in my case, only index.php was being found and so only the contents of index.php were being returned.

When a person browses to your website, WordPress selects which template to use for rendering that page. As we learned earlier in the Template Hierarchy, WordPress looks for template files in the following order:

1. Page Template — If the page has a custom template assigned, WordPress looks for that file and, if found, uses it.
2. page-{slug}.php — If no custom template has been assigned, WordPress looks for and uses a specialized template that contains the page’s slug. A slug is a few words that describe a post or a page. If the page slug is recent-news, WordPress will look to use page-recent-news.php.
3. page-{id}.php — If a specialized template that includes the page’s slug is not found, WordPress looks for and uses a specialized template named with the page’s ID. If the page ID is 6, WordPress will look to use page-6.php.
4. page.php — If a specialized template that includes the page’s ID is not found, WordPress looks for and uses the theme’s default page template.
5. index.php — If no specific page templates are assigned or found, WordPress defaults back to using the theme’s index file to render pages.

I realise this is just the basic knowledge needed but I hope to discuss this further. Writing here helps me understand and get my thoughts clear.

Setting up the Plex container in unRAID 6

In this post I am going to discuss how I went about adding the Plex container in unRAID 6. It's a fairly straightforward process and didn't cause me many headaches thankfully. I was originally running the server from my desktop but that wasn't an ideal solution because I don't leave my desktop on all the time.

Enabling Docker

The first step involved here was enabling Docker. To do this you simply navigate to the Settings tab, click Docker, and then use the drop down menu to enable Docker. PlexMediaServer is one of the default docket templates that comes packaged by lime-technology in unRAID 6. Navigate to the new Docker tab and you will see a section named 'Add container'. From there you want to choose 'PlexMediaServer' under the limetech heading. 

There is only one required folder named 'config' for this docker but you're going to want add more. The config folder does exactly what it says on the tin - Stores the configuration settings for this particular docker. I originally made the silly mistake of pointing this folder to a directory on the flash drive running unRAID. As soon as I rebooted the server I lost all the configuration I had spent the previous setting up - bummer. So for this directory you're going to want to specify a directory on the array. I created a folder called 'DockerConfig'.

In order to add any media you will also need to specify these directories too. I added one named /movies pointing to /mnt/disk1/movies and another named /series pointing to /mnt/disk1/series. 

All that is left now it to allow unRAID to create the docker container. Simple as.

Configuring Plex

There wasn't a whole lot of configuration required with Plex assuming you only want to use it locally within your home. If you plan on streaming media externally you will need to setup remote access. There are three steps required in doing this. The first step required is to sign into your Plex account, assuming you created one. If not you will need to register an account. The second is port forwarding - By default Plex will use port 32400 but you can specify another port if you prefer. You will need to forward this port to the IP of your server. Lastly you need to edit the settings of your plex server for remote access and manually specify whatever port you chose by ticking the box to manually specify. 

unRAID 6 benchmarks

Now that I've got unRAID up & running I thought it would be interesting to run some benchmarks so I could determine what kind of speed to expect. I have purchased a gigabit switch and cat6a ethernet cables for wiring everything up so this as fast as I can get for now. The program I used to run these benchmarks is called 'CrystalDiskMark'. This is with two WD Red 3TB drives with one acting as a parity disk.

I don't think that's too bad considering I don't have a cache device set up yet. Still slower than my desktop mechanical drive for both sequential read and write speeds but I doubt I will notice the difference when it comes to real world usage - Hopefully anyway. Parity certainly had more of an impact on the speeds than I would have liked. My internal 1TB WD Blue mechanical drive clocked the below speeds. Much faster for sequential reads and writes but a hell of lot slower for the 4k metrics.

I'll probably revisit this in the future when I set up my cache device.

Benchmarking my desktop SSD

My desktop currently has a 120GB M500 Crucial SSD installed for booting my OS and related applications. It's not exactly a top-of-the-line drive by any means but it's more than enough for every day use. The spec sheet for this model claims I should be getting up to 500 MB/second reads and 400MB/s writes. So when I saw the results of my CrystalDiskMark test I was underwhelmed to say the least. It's worth nothing that this drive was 75% full at the time of the test so I understand this has the potential to affect speeds - But not this much!

56MB/s sequential writes?? Time to figure out what's going on here..

Troubleshooting steps

First off I needed to ensure that AHCI was enabled. AHCI stand for Advance Host Controller Interface. This is a hardware mechanism that allows software to communicate with Serial ATA (SATA) devices such as SSDs. Windows supports AHCI out-of-the-box by default but just to be sure I went into device manager to confirm the AHCI controller was enabled and running.

So it's enabled - Great! Now I just need to confirm that the SSD is being managed by this controller. Right click the controller, choose properties, then navigate to the 'Details' tab. In this section you are greeted with a drop down menu where I chose 'Children' and could see my SSD listed so AHCI is definitely enabled.

Then I needed to confirm that 'TRIM' was enabled. TRIM support is essential for an SSD to run the way it should to avoid slow writing times. This command allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally. To test if this is enabled you can run the command "fsutil behavior query DisableDeleteNotify". If this returns as 0 then TRIM is enabled.

The next step was to make sure I was at the latest revision of the firmware. The firmware download for my SSD comes as an ISO package so I stuck it onto a USB using unetbootin and made a backup of my current SSD before proceeding - I've had enough bad experiences to warrant backups! Thankfully the installation completed successfully without any issues and I was upgraded from MU03 to the MU05 revision. Rebooted and went through another benchmark with CrystalDiskMark. No improvement whatsoever.

So considering there was little to no change in the speeds I figured I would confirm the results with another benchmark tool - Atto disk benchmark. Now I'm seeing more along the lines of the expected speeds! At my maximum I reached over 500MB/s reads and maxed out about 140MB/s writes. I'm still a little disappointed with the write speeds though but this is a start at least.

As this was an SSD I was recommended to test out 'AS SSD Benchmark' which also confirmed that AHCI was enabled and my alignment was okay. This reported speeds were pretty much along the same lines as what I've seen so far with write speeds being reported between 113MB/s and 134MB/s. Still disappointing.

I went ahead and asked someone else to run the same test on their Crucial M4, which is an older model than mine. He was clocking double my write speeds with similar read speeds using the same test config as me. Only other difference between his test and mine was that his drive has higher total capacity with about 50% free whereas I only had 25% free. I went about reducing the space consumed on my drive and then re-ran the test only to receive roughly the same numbers again..

The conclusion

After a bit more digging I realised this was down to false advertising rather than anything being wrong with my drive / configuration. The M500 series drives are capable of up to 400MB/s write speed at the higher capacity spectrum of drives. My specific model - CT120M500SSD1 - I found is only capable of about 130MB/s which more or less matches up with the speeds I was recording in some of the benchmarks. Here is a screenshot from the product page on newegg:

Installing unRAID 6 on my HP Proliant Gen8 Microserver G1610T

In this post I am going to discuss how I went about installing unRAID 6 on my HP Proliant Microserver G1610T.

Downloading the unRAID image

Before going about installing unRAID I was under the impression that it would come in an ISO package like every other OS. However unRAID just comes as a package of files with a 'make-bootable' executable inside. Preparing the USB is easy! First of all your USB needs to be formatted to FAT32 and the volume label must be set to UNRAID in capital letters. 

Then simply transfer all the files to the root directory of the USB (i.e. not in a folder) and then run the 'make-bootable.bat' file as administrator. (Right click -> Run as administrator) A CMD prompt will appear just asking you to confirm you want to proceed - Press any button to continue and hey presto job done.

Now you just need to eject the usb from your computer, connect it to the internal USB slot of the microserver and boot it up. Mine booted into the USB straight away without editing any BIOS options. After successfully booting up I was able to navigate to http://tower from my desktop and was greeted with the unRAID web GUI. It really was that easy!

Licensing

Before you're able to do anything inside unRAID you need a license key. Upon first installation you're entitled to a 30 day evaluation period to test out the software. To activate your license navigate to 'Tools -> Registration'. You will need to enter in your email address so the license URL can be sent to you which you then paste into the box provided.

After that you're pretty much good to go! 

New components for my HP G1610T Gen8 Microserver - Upgrades!

I decided it would be best to invest some more money into my microserver rather than trying to struggle through with the limited resources available in the server itself. I also needed some hard drives to full up the drive bays for my NAS. 

What did I buy?

2 x 3TB WD Red NAS drives
1 x 2 Port SATA Controller
3 x Cat6a ethernet cables
2 x 8GB ECC DDR3 RAM

The NAS drives will obviously going into the bays available at the front of the server so I can set up my NAS. As I only have two drives at the moment this means the array will only have 3TB usable space due to the parity disk. Realistically that is all I need to start with as my media collection is only about that large at the moment. The SATA controller card I bought because the internal SATA connector only runs at SATA I speeds while this PCI card runs at SATA III. This will be used to connect up my cache devices if I ever get around to implementing that. 

The requirements for running unRAID are pretty minimal compared to FreeNAS with unRAID only requiring about 1GB of RAM if you have the intention of running it as a pure NAS system. However once you start playing around with containers and virtualising machines you will understandably get tight on resources. With that in mind I decided it would be best to upgrade to 16GB RAM which is the most this machine will accept. This didn't come cheap at about €160 for the two stick set - ECC RAM is bloody expensive.

Lastly I decided to invest in some decent cat6a cables for connecting up my server and desktop to the network. I've been running on cat5e cables for quite a long time because in all honesty I just had no requirement for the additional benefits in cat6 cables. Now that I will be regularly transferring files to and from the NAS I felt the requirement for additional cable bandwidth.

How the application server works in unRAID - What is Docker?

I'm going to take you back to one of my first posts where I explained what the purpose of a hypervisor is and what the differences between a level 1 and a level 2 hypervisor are. I think this would be useful to understand before proceeding with this post. 

Basically the idea behind a hypervisor is that it has the ability to emulate hardware in such a way that an operating system running on the hypervisor has no idea that it is not a physical machine. By creating multiple VMs you have the ability to isolate applications from each other, for example you might have one VM for torrents and automated media management, and then another for development work. This is all great in theory but the issue with this is that virtualisation is resource intensive! The alternative to deploying Virtual Machines is using 'containers'. Containers are similar to virtual machines in that they also allow for a level of isolation between applications but there are some significant differences..

What's a container? How does it differ from a Virtual Machine?

Going back to the idea of a virtual machine - it helped us to get past the idea of a one server for one application paradigm that was formerly common in data centers and enterprise. By introducing the hypervisor layer it allowed for multiple different OS to run on the same hardware so that many different applications could be used without wasting resources. While this was a huge improvement it is still limited because each application you want to run will require a guest operating system, it's own CPU, dedicated memory and virtualised hardware. This lead to the idea of containers..

unRAID makes use of Docker containers. Similar to the idea of a virtual machine Docker containers bundle up a complete filesystem with all of the required dependencies for an application to run. This will guarantee that it will run the same way on every computer that it is installed on. If you have ever done any development work you may understand the frustration of developing an application on one machine, and then deploying it on another machine only to find out that it won't launch. Docker helps to do away with this by bundling all the required libraries etc. into one lightweight package with the 'Docker Engine' being the one and only requirement. The Docker Engine is is a program that allows for containers to be built and run.

Fundamentally a container looks similar to a virtual machine. A container uses the kernel of the host operating system to run multiple guest instances of applications. Each instance is called a container and will have it's own root file system, processes, network stack, etc. However the fundamental difference being that it does not require a full guest OS. Docker can control the resources (e.g. CPU, memory, disk, and network) that Containers are allocated and isolate them from conflicting with other applications on the same system. This provides all the benefits of traditional virtual machines, but with none of the overhead associated with emulating hardware.

The Docker Hub

One of biggest advantages Docker provides is in its application repository: The Docker Hub. This is a huge repository of 'Dockerised' applications that I can download and run on my microserver. With unRAID and Docker it doesn't matter if it's a windows or linux application, I can run it in a docker container. Really cool stuff.