UNRAID – 180TB Storage with Twin Cache and Parity

Why Unraid?

For years, I managed my own Plex media server using a stack of relatively unprotected disks, with BackBlaze as my backup solution. It was simple and effective, but as my data grew to nearly 100TB, I became increasingly concerned about its lack of protection. I needed a cost-effective solution that wouldn’t break the bank.

After extensive research and years of experience with RAID, I realized that RAID wasn’t the right path for me, mainly due to the high cost of hard drives required for proper protection. Then I discovered Unraid. I had heard many positive things about it, along with some criticisms, but it seemed like the perfect fit for my needs.

What is Unraid?

Unraid is quite different from traditional RAID systems. Unlike RAID, Unraid does not use disk striping. However, it does support the use of parity disks for data protection, which was my main interest.

When configuring Unraid, there are several methods for distributing data across the storage pool. The most popular method is “Highwater.” This method is favored because it spreads data across multiple disks. If more disks fail than you have parity for, at least your data isn’t all on just one or two disks, which can happen with the “Fill Up” method.

Parity disks are straightforward: There are only two types of disks in the world, those that have failed and those that just need more time to fail! With one parity disk, you can withstand the loss of one storage disk without data loss. With two parity disks, you can handle the simultaneous failure of two storage disks, and so on. The chance of two disks failing at the same time is very low, and more than two is extremely rare. However, you need to assess the value of your data and how much you’re willing to invest in protection. I recommend always having an offsite backup plan, such as CrashPlan for budget-friendly options or BackBlaze B2 if you have more to spend. Remember, your parity disk must always be the largest disk in use, meaning it must be larger than your largest storage disk.

Unraid writes each entire file to a single storage disk rather than striping it across multiple disks, which is why it’s called “unraid.” It uses sophisticated techniques to make the pool of storage disks appear as one large disk. This means that if you were to remove a storage drive and examine its contents, you would find whole, intact files rather than fragmented data, as you would on a RAID disk. This feature can be particularly helpful for data recovery in worst-case scenarios.

First I will list all the items I used in my Unraid build, some may seem overkill to others but I had my reasons. Some I made mistakes and undershot what I should have used and I will explain those failures so that you don’t make them.

Motherboard – MSI MAG B550 TOMAHAWK AM4 AMD (6 onboard sata ports)
CPU – AMD Ryzen 5 5600G
CPU Thermal – Thermalright Peerless Assassin 120 CPU Air Cooler, 6 heat pipes and dual 120mm fans. This thing is a BEAST!
Case – Fractal Design Define R5 Black (this case has the ability to hold 11 disks)
Memory – 2x16GB Corsair Vengenance LAPX DDR4 3200
Power Supply – EVGA 500W ATX (this was my first mistake, it could not handle the power of running 11 sata disks and burned up in three days!) The second power supply I went with was the ARESGAME 1300W ATX and I have had no issues)
Cache Disks – WAVLINK SSD 4TB PCIe M.2.2280 and KingSpec XG 7000 4TB M.2.2280 PCIe) Why two different brands? I don’t like to put all my eggs in the same basket.
HBA Controller – SVNXINGII 9207-8i 6Gbs SAS with 8 SATA disk support, includes cables. DO NOT use a standard PCIe SATA Controller, it is a nightmare to get one to work correctly with Unraid so that the disks are presented at bootup. The HBA controller was simple plug n play with Unraid.
Power Splitters – Since I was installing 11 SATA disks I needed more power connectors than the power supply had, I used Startech PTO2SATA 6in Power Y Splitters.
Case Fans – Fractal Design Dynamic X2 PWM 140mm. The bare case only contains two fans, not enough for 11 SATA disks, I purchased 4 more fans to install.
Parity Disk – 18TB refurbished Seagate Exos X20 disk. This was my second mistake, I purchased a refurbished drive for a parity drive which was my data protection, a noob move on my part. Less than a week after the build my system was in the state of rebuilding a storage disk when the parity disk failed and caused me to lose all the data on that storage disk! Going cheap does not pay sometimes, I ended up purchasing a New 18TB disk to replace the parity disk.
Storage Disks – I purchased 11 SATA 14-16TB disks, mostly refurbished from Newegg. Unfortunately, I’m starting to regret this decision as two of the drives have already failed within a month of use. Upon checking the SMART info, I discovered that these drives had been online for over 4 years! I will never purchase refurbished drives again, especially from Newegg, which seems to source from companies that excessively use these drives. Many of these companies appear to be resetting the SMART data and selling the drives without proper refurbishment. On a positive note, Newegg, GoHardDrive, and Max Digital were all accommodating in processing refunds for the faulty drives.
Disk Tray – ICY DOCK Hot Swap 3 bay 3.5″ SATA Enclosure. I used this to change the two 5.25 bay enclosure at the top of the Fractal case to support three 3.5″ SATA disks. Works great and I have had no issues, I keep my parity disk as well as a couple storage disks.

UNRAID Licensing – I opted for the Lifetime license at $249. While there are cheaper options available, they come with restrictions on the number of storage devices you can connect or limit OS updates. Ultimately, it’s a personal choice, but I’m just relieved it’s not a subscription model like so many others these days!

Unraid offers a multitude of features, far too many to cover in this article. For a comprehensive list, you can explore features such as Docker Applications, Virtual Machines, Unraid Connect, and VPN Manager. I’ll focus on Docker applications, sharing my likes and dislikes. The Community Apps section alone boasts thousands of free Docker applications!

The Unraid OS operates from a bootable USB drive, so it’s crucial to invest in a high-quality USB. Since Unraid runs continuously 24/7, most standard USB drives aren’t built to withstand such constant use. I opted for the 4GB SLC AF4GUFNDNC(I)AACXX from Digi-Key, priced at $56 USD. I bought two—one as a backup. This industrial-grade USB is designed for continuous operation. Keep in mind that Unraid OS is tied to the physical USB, so if it fails, you’ll need to contact their support to transfer the OS to a new USB.

System BIOS – After assembling and installing all the hardware, your first step should be to verify that your BIOS is up to date. Often, by the time the motherboard reaches you, several BIOS updates may have been released. Ensuring you have the latest version will help you start with the most optimized and stable system possible.

After you first boot in the Unraid OS you will need to assign parity disk(s), storage disks and cache disk(s), the example below is how i assigned mine:

You can see I have one parity disk (which is in parity-sync at the moment hence the orange triangle), 10 storage disks of varying sizes, and two cache disk in a raid-zero pool to give me 8TB cache total. You can do raid-1 which is basically a mirror if you feel you need to also protect the data in cache before it is written to storage disks. Most of my data I pass straight to array and not cache-> array, so it wasn’t a concern for me. Since this is media files I don’t really need to use the cache for that since I am not writing to the server all the time, mainly reading from it. I do use the cache-array for things like app data, system, ISOs.

In total there is currently 136TB of storage space, however I have 100TB of data that is transferring to it as we speak, so I will be expanding the storage, about three more drive is all I can add then I will have to build a second Unraid System. 😉 There is no end when it comes to media hoarding!

For many years, I successfully ran Plex, Sonarr, Radarr, Lidarr, Readarr, and Sabnzbd on VMware virtual machines on a full-size rack server. Wanting to push the envelope, I decided to install all the *arrs as Docker apps on Unraid. The installations were straightforward—just a few clicks and some configuration settings, and everything was up and running. I was so proud and happy!

However, the next day, my Radarr app failed due to a corrupted database. With hundreds of movies listed, I would have lost them all if I hadn’t done a backup (which I did) and still had my old VMs. I noticed many people online complaining about *arr database corruption with Unraid. So, I quickly moved everything back to my original VMs and plan to keep it that way. I did leave Readarr on Unraid for some testing. Currently, I run CrashPlan, Overseer, and Readarr as Docker applications on Unraid.

While moving 100TB of data from one system to unraid is in itself a challenge, I mainly use powershell to run robocopy commands and monitor the output using BareTail (love this app). You have to be patient with unraid in the beginning while it is doing parity-sync, cache moves and disk clearing (which I recommend doing first before you assign the disk to your array else doing a disk clear in the array will slow everything to a crawl!).

IMPORTANT! use the best quality disks you can afford and to the point of the value of your data to you, and always use new versus refurbished disks if you can afford them. You will beat your head against the table with 50% of refurbished drives! You have had your fair warning!

Lesson Learned – As I mentioned earlier, I had purchased refurbished disks for storage and parity from NewEgg, tempted by the low cost of $89 for 14TB. Unfortunately, this decision came back to haunt me. First, a refurbished 14TB storage drive failed. I replaced it, and as expected, it began rebuilding from the parity drive and was being emulated. The next morning, the refurbished parity disk also failed, resulting in the loss of everything on the 14TB storage that was rebuilding 😞. Thankfully, I had a backup on BackBlaze, but downloading 14TB of data from the cloud was neither fun nor fast. I love BackBlaze and its been good to me but backing up from Unraid to their B2 storage at $780 a month for 130TB is just not going to work for me! CrashPlan Enterprise unlimited cost me $120 a year, a savings of $9,240 over BackBlaze!! I understand there are many complaints about CrashPlan in the past by others, but this is simply my backup plan to my backup. The parity being my #1 protection, and I plan to add a second parity disk just for extra precaution.

Updates – I have a second 18TB parity drive on order. While the chance of two drive failures occurring simultaneously is extremely rare, I prefer the added protection since I’m still using several refurbished drives. Additionally, I’m upgrading my ASUS RT-AX88U router to an ASUS RT-BE88U router. This new router features 2.5G LAN ports, which will significantly boost my LAN speed when transferring files, as my MSI motherboard natively supports 2.5G. It also includes a 10G SFP+ port and WiFi 7, providing an option for future upgrades.