Review – The OWC ThunderBay Flex 8 Workflow Supercharger

September 16, 2020

Get a hands-on look at OWC's direct-attached Thunderbolt-3 RAID chassis. Plus, (3) configuration ideas for post production professionals.

OWC’s ThunderBay Flex 8 – What is it and who’s it good for?

It’s no secret, I’m a gear-head when it comes to post production, computers, and workflow. I love new equipment and coming up with ways of working faster. When OWC reached out to Mixing Light to review their new ThunderBay Flex 8 – I was excited to try to push it to its limits. I wanted to see how I can use it in my workflow as a colorist and figure out other use cases for our business.

FCC Disclosure: Mixing Light is an affiliate of OWC and affiliate links appear throughout this article (which help support Mixing Light, at no cost to our members). OWC provided Mixing Light and me, Joey D’Anna, a Flex 8 populated with drives for the purposes of review, testing, and writing this article.

OWC’s ThunderBay Flex 8 is an innovative, customizable Thunderbolt3 expansion chassis. (click to enlarge all images in this article)

In this review, you learn the hardware options the Flex 8 offers and then you see the results of its real-world performance and how I am utilizing it in my suite.

ThunderBay Flex 8: Hardware Overview

The ThunderBay Flex 8 is, at its core, a direct-attached Thunderbolt-3 RAID chassis (click through for current pricing and its product page). It contains eight drive bays and is built for high-speed local storage on a Thunderbolt capable Mac or PC. What makes the Flex 8 different is that it’s more than just a drive chassis. In addition to the eight drive slots, the Flex 8 includes:

  • A multi-port dock, adding USB 3.1 and USB-C ports to the front of the unit
  • A built-in high-speed card reader for SD and CFexpress cards
  • (2) PCI-e slots
  • An 85w powered Thunderbolt3 port – capable of connecting additional peripherals or charging a laptop
  • An additional 15w Thunderbolt3 port for powering lower watt peripherals, keeping them from monopolizing the 85w port
The Flex 8 has built-in card readers plus USB-C/USB 3.2 ports. These inputs make connecting media cards or external drives very easy and convenient.
Thunderbolt3 laptop users can charge their machines with the built-in 85W Thunderbolt3 port. Notice the additional lower wattage port for less power-hungry peripherals with simultaneous hook-up.

U.2 SSD: Reconfiguring the top four slots

One cool thing about the Flex 8 is that unlike other SATA/SAS drive solutions; the top 4 drive bays are U.2 capable. U.2 SSDs may look like a typical SATA SSD, but they connect over high-speed PCI-e lanes, giving them incredible performance. Even a single U.2 SSD provides a massively fast cache drive, and combining multiple into a RAID0 will yield tremendous speeds.

U.2 SSDs fit in standard drive bays but use much faster PCI-e connections for superior performance.

Flexibility – It’s Right in the Name!

Totaling up all these features and you have a system allowing a slew of different workflows. A few examples include:

  • Utilizing the (4) U.2 slots – the top row in the unit – for creating a super-high-speed SSD RAID0 for cache
  • Using the built-in card reader to copy client media quickly
  • Leveraging the open PCI-e slot to add additional storage or video capability

The PCI slot is probably my favorite part. It’s a great place to add 10 Gigabit ethernet for connecting to shared storage – or to add a DeckLink card to a machine without PCI slots (like a Mac Mini, Macbook Pro, or iMac.)

The second, empty PCI slot is a perfect place for a DeckLink card or other PCI-e cards.

To SoftRAID or not to SoftRAID?

It is worth mentioning that the Flex 8 is not a hardware RAID. Running it in a RAID5 configuration requires a RAID solution.

The Flex 8 comes with a license for OWC’s SoftRAID software, which is a powerful software RAID system for Windows and macOS. Here’s the thing – the SoftRAID driver is included in default macOS installations, so if you buy a Flex 8 preconfigured in RAID5 – you can just plug it into any Mac and see the volume instantly! If you are on a PC – OWC offers SoftRAID that works in RAID0 and RAID1 (mirror), with support for RAID5 coming soon. Windows 10 also has built-in software RAID0 and RAID5, which you can configure using the disks in the Flex 8.

But another cool option – the Flex 8 lets you install a dedicated hardware RAID card.

The built-in SATA interface card can be replaced with hardware RAID cards if your workflow needs it.

I mentioned earlier that the Flex 8 has two built-in PCI slots. In the default configuration, a SATA controller occupies one position – connected to the drive bays. You can replace this controller with either a SAS controller (if you want to utilize SAS disks) or a SATA or SAS hardware RAID controller. The latter configuration is powerful if you’re using the Flex 8 for cross-platform mobile storage. You just format the hardware RAID volume in HFS+ and access it on either Mac or a PC (with software like MacDrive) – without worrying about the type of software RAID being used.

SIP, Secure Boot, and installing the SoftRAID driver

The SoftRAID driver installed with the macOS isn’t usually the most current version. If you want the latest and greatest SoftRAID driver, you’ll need to follow a few steps to install it. If your Mac has a T2 security chip, this involves adjusting some boot security permissions – which warrants a short discussion.

To install the latest SoftRAID driver – you need to disable Apple’s Secure Boot. There are a few essential things to know about this (it’s not as bad as it sounds):

  1. You do not have to install the latest SoftRAID driver. Currently, SoftRaid 5.8.1 is shipping with macOS and it’s perfectly capable, performs well, and is reliable. If it weren’t – Apple wouldn’t include it in shipping versions of their operating system. Personally, I’ve been running the Apple-shipping version of SoftRAID for both the Flex 8 and the older ThunderBay4 I’ve used for years without concern.
  2. There is a BIG difference between disabling Apple’s Secure Boot for a RAID driver and disabling Apple’s SIP (System Integrity Protection). SIP is a feature introduced in OSX 10.11 that continually monitors all system files, making sure no software (malicious or not) messes up your OS installation. Disabling Secure Boot allows essential 3rd party software to load up in the first few minutes after power-up; but SIP is still in the background protecting your operating system.
  3. I’ve seen quite a few pieces of post-production software that do not work unless you permanently disable SIP – and I always recommend avoiding that software. SIP’s only job is protecting your Mac. If a developer is doing something that requires a SIP disable – this is very likely from bad programming on their end. Consider that requirement as a warning bell.
  4. OWC’s SoftRAID drivers do not require disabling SIP – so I wouldn’t fear in following OWC’s instructions for installation. However, if you are like me – and like to keep things as close to factory as possible – I’m sure Apple will eventually include newer versions of SoftRAID in future OS releases. I’m happy to wait on Apple to install those drivers in a future OS update.

For more information, OWC has published a blog post with more detailed information on the SIP and Secure Boot topic.

ThunderBay Flex 8: By-The-Numbers Performance

So – how does the Flex 8 perform? In my configuration, I have a single high-speed U.2 SSD for fast caching of things like image sequences, and I have a seven disk RAID5 for backup storage of larger client media files.

Flex 8’s performance is impressive. Editing and grading off of the spinning disk RAID is consistently real-time, with no hiccups or issues. Grading from image sequences, or from caches on the U.2 SSD, also performs well.

Blackmagic Design Disk Speed Test

While benchmarking the Flex 8 – I found some interesting things about doing disk speed tests. Even on the same machine – the type of test, and how it reports speed – can be wildly different. Personally – I don’t think disk speed tests are the be-all end-all measure of performance. But they do give us a clue as to how much data can move through both a RAID – and your individual system.

First – the BMD speed test. The single U.2 SSD pulled over 2300MB/s read speed. A RAID0 of more U.2s would be even faster. The seven disk RAID5 also performed well, getting over 650MB/s write and 510MB/s read speeds. More than fast enough for almost any modern post-production media format, and this is in a redundant RAID5 configuration. Configuring disks in a RAID0 will net even faster speeds.

This configuration has (1) U.2 SSD with (7) spinning hard drives in a RAID5 stripe.

But after doing some math and talking to the folks at OWC – I found that while excellent, these numbers didn’t seem to fully reflect what the system was capable of. So I looked a bit deeper, and while the BMD speed test was reporting a 510MB/s read, the Mac’s Activity Monitor (with nothing else running or happening on the system) was reporting much more bandwidth:

The BMD speed test doesn’t seem to give the whole story for read speeds, at least on my Mac Mini

AJA System Test

So I decided to try a different test. Using the AJA System Test, with the image frame size set to UHD (a typical workload for my projects) – I consistently get much higher speeds:

The AJA speed test reported way better performance than the BMD speed test and is in closer line with the Mac’s Activity Monitor.

So at the end of the day – there is no question, the Flex 8 performs very fast. Different workloads and different tests with different apps running will yield varying results (even on the same system!) but in actual, real-world use, the performance is excellent.

And the PCI slot? It is capable of 4 PCI lanes (the maximum possible with Thunderbolt3). I’m using it to host a DeckLink 4k card – and it works perfectly, even in 10 bit, 4K Resolutions. It’s functioning seamlessly as if the card was inside the computer, and has never had any issues dropping frames or hanging up. I really can’t tell the difference between the DeckLink inside the Flex 8 and a DeckLink inside the computer directly.

My Mac Mini has no PCI slots, but the DeckLink works perfectly in the Flex 8.

Is OWC’s Flex 8 the right solution for you?

The Flex 8 is configurable for a wide array of workflows.

I’m laying out three different example configurations for three different workflows (including my own). I think you’ll see that the configurability of the Flex 8 is it’s greatest strength; it has multiple use-cases. These use-cases should help you decide if it’s right for you.

Configuration 1: A solo colorist’s primary workstation

Are you running an independent color grading or editing business? The Flex 8 is an excellent primary storage solution for a solo colorist or editor.

If you are a solo colorist, editor, or a bit of both – the Flex 8 is a fantastic option for direct-attached storage. Let’s configure one for use with a beefy iMac or iMac Pro setup:

In this configuration – you have a massive 60TB, high speed, fault-tolerant RAID5 storage. It’s fast enough for most client work – but for heavier raw or image sequence workflows, you also have a 16TB super high speed U.2 RAID0.

For most clients, you store your media on the fault-tolerant RAID5 volume – and cache to the SSD RAID0 for performance.

Utilizing the Flex 8’s PCI slot for a DeckLink Mini Monitor 4k – the solo colorist/editor gets a full 4k SDI output at a reasonable cost of $200. A similar, standalone thunderbolt box for SDI output costs over twice that. The Flex 8 also offers a second thunderbolt port – so if you need more GPU performance in the future, you can add an eGPU chassis.

As a bonus, you get the easily accessible front-mounted USB ports and a high-speed card reader for connecting client drives/media.

Configuration 2: A Colorist Assist Station

This configuration is how I am using the Flex 8. Let’s say you are a colorist, with a high spec’ed workstation, connecting to existing high speed shared storage. Assist stations are a great way to offload non-color tasks like conform/editorial/graphics/email/etc., and make a fantastic platform for running software scopes like ScopeBox or the upcoming/new OmniScope.

In my suite, I’ve connected the Flex 8 to my assist station for backup storage, and video I/O for scopes.

For an assist station configuration, I prefer the most recent generation Thunderbolt3 capable Mac Mini, and add:

  • A Flex 8 with (8) 12TB spinning disks
  • A Decklink SDI 4k

Just like the configuration above, you are saving a good amount of money by using a much cheaper PCI card for SDI I/O. I’ve chosen a card with inputs as well as outputs since this configuration runs my software scopes.

But why so much disk space? Because an assist station is a perfect tool to do regular backups of your current project media! I use the Mac Mini’s built-in 10G ethernet to connect to my shared storage – and then I use rsync or Carbon Copy Cloner to make nightly backups of all my current projects’ media.

This configuration gives me a great level of disaster recovery.

If I suffer a major failure on my shared storage system and I’m on a tight deadline, I can simply unplug the Flex 8 from my assist station, plug it into my main Mac Pro, and continue working with no interruption! That’s a great fall-back plan in case if a big failure, and since the Flex 8 is fast enough to work off of directly – I can transition to it at a moment’s notice.

Configuration 3: DIT or on-set Storage Solution

The Flex 8 is also an ideal solution for on-set storage and media transfer. Since it has an 85W Thunderbolt port, you can connect it to a modern Macbook pro – using it for both storage and powering the laptop.

The Flex 8 is a great on-set solution and compatible with OWC’s U.2 Interchange System

An example on-set configuration includes:

  • (4) 12TB spinning disks
  • (4) 8TB U.2 SSDs
  • The OWC U.2 Interchange System, with multiple U.2 sleds
  • A DeckLink Mini Monitor 4K
  • Optionally – a hardware RAID card, making connections between Macs and PCs easier

Again, I’m choosing to populate the PCI slot with a DeckLink card for the video I/O – and similar to my colorist/editor configuration – I’m opting for a cheaper, output-only card, as a DIT needing an SDI input is unlikely.

Leveraging OWC’s interchange system for on-set media management

One great use for the Flex 8 on-set is that you can combine it with OWC’s U.2 Interchange System, smoothly moving SSD’s between systems. This system allows you to put removable SSDs into the Flex 8’s top 4 slots, copy media to them from the main RAID5, and then pull them out to hand them off to clients, editors, graphic artists, etc. – after a swift copy.

The U.2 interchange system is pretty cool on its own. It consists of a special sled, and a PCI dock to convert a small Thunderbolt3 PCI chassis called the Helios 3S into a system for exchange U.2 SSDs over Thunderbolt 3.

The OWC U.2 SSD Interchange System allows quick exchange of media on set and to/from clients

Operationally, this means for a DIT to hand off an SSD:

  1. Copy media from their main RAID5 to one of 4 U.2 SSDs in the top row.
  2. Use the OWC Dock Ejector software to eject the SSD from the OS
  3. Remove that SSD from the chassis
  4. Remove the SSD from the Flex 8’s drive rails
  5. Handoff the SSD sled to anyone else with a Helios chassis and dock, for quick access
OWC’s SSD carrier system allows for the secure, safe transport of high-speed SSDs. But it does require manipulating screws – which can be a bit of a hassle.

Honestly, having to remove the Flex 8 rails is a bit of a hassle, but it is only four screws. However, a more advanced configuration is:

  • Add a Helios dock connected to the Flex 8’s second Thunderbolt port and copy to SSD’s via Thunderbolt. Plus, a slot opens up in the Flex 8 for additional disk storage.

Final Thoughts and Conclusion

As you can see – Flex 8’s greatest strength is its configurability. You can build anywhere from mild to wild for multiple workflow needs. I’ve only scratched the surface here with my three example configurations, as you can use the PCI slot to add tons of different workflow-specific tools, like storage interfaces, specialized audio cards, and more.

From a cost standpoint – I think Flex 8 is a fantastic deal. For me – a single Flex 8 has replaced three different dedicated devices on my assist station:

  • A card reader for copying client media
  • A Thunderbolt SDI I/O device
  • A Thunderbolt direct attach RAID for media backup

The Flex 8 is less expensive and easily customizable. Plus, if your needs change in 12 months, it’s easily reconfigured – extending its useful life.

If you’d like more details on the ThunderBay Flex 8 check out its product page.


Homepage Forums Review – The OWC ThunderBay Flex 8 Workflow Supercharger

  • Temesgen G

    As always, this was a fantastic and thorough article. Thanks Joey. My question for you is if I put my decklink card in the flex 8, how would it properly receive the signal from my Resolve? Is the thunderbolt cable carrying the signal for both the hard drives for read/writes and also the Resolve?

  • Joey D’Anna

    Thanks! Yes – Thunderbolt3 actually carries PCI-e data, unlike USB/FireWire/ETC. This means when you install a DeckLink in the Flex 8 and plug it in, the blackmagic desktop video driver sees it just as if it were in a PCI slot in the computer (even if like my mac mini – the computer doesnt have any pci slots!)

  • Robert Sharpe

    Hi Joey,

    Just wanted to seek some confirmation: the top PCIe slot has to be a SATA or SAS controller? You can’t remove that card and have 2 different PCIe cards? For example we want to have a 10G ethernet card and a SAS card to connect to both server and LTO machine to an iMac.

  • Jose Santos

    Hey Joey! Just raid this review again am I’m seriously leaning on ditching my NAS, which we talked about, getting this and a mac Mini. What are your thoughts on this configuration:

    Thunderbay Flex 8 with six 7200 RPM HDD’s and two U.2 SSDs for caching connected via TB3 to a Mac Mini.

    The Mac Mini would connect via 10gb Ethernet to my machine and serve as the NAS system, as well as running Scopes and a remote Resolve DB so that I could also use it to render the Projects to ProRes.

    Alternatively I could also connect both machines via TB3 to the Thunderbay since my PC has TB3 however I don’t know which file system to use then…

    Is that too much to put on a Mac Mini? I’ll be replacing my Radeon VII soon for something more powerful and I could put it on the Mac Mini as an eGPU.

    Let me know your thoughts!

  • Joey D’Anna

    I think you could do 2 different PCI cards – but then you would loose all the functionality of the drive bays. They all connect internally to the SATA card that the unit comes with in the top slot. A SAS card that has internal connections may work – but honestly i’m not 100% sure.

  • Joey D’Anna

    Interesting! I think it could work, but my concerns are 1. That is a lot to put on a mac mini in terms of expectations. I don’t mean it wouldnt work – i just mean mac mini’s are great but they arent exactly premium hardware, im not sure if i would run one as a primary NAS server because if it dies, you are just out of luck. My mac mini assist box runs pretty hot and sometimes crashes (not often, im talking maybe once every month or two) – but mac minis definitely get hot.

    and 2 – you definitely cant connect both machines via TB3 to the thunderbay – as it is a direct attach storage, it can really only be connected to one thunderbolt host at a time.

  • Ciaran Lee

    Hi Joey, thanks largely to this review, I have a Flex 8 on order.

    I’m still a little unsure how I should split between spinning disks and U.2. I don’t want to pay for more U.2 performance than I need (and give up capacity), but equally, don’t want to be caught short.

    So, 6 X 10tb Ironwolf Pro drives for RAID 5 storage, and cache to one WD Gold U.2 3.84TB, adding another for a RAID 0 config in the future if I need it.

    Or, 7 X 10tb Ironwolf Pro, with a single U.2, on the basis 7 spinning disks will give all of the performance I need?

    I shoot and edit and use 4k XAVC I footage from a Sony FX9 90% of the time. Mostly single-cam and two-camera projects, usually of 5-15 minutes in length. Usually have 8-10TB of active media between a couple of on the go projects.
    I cut and colour in Resolve extensively, but do not use Fusion much. Currently on a 16″ MBP but will likely buy something beefier next year.

    Thanks so much,

  • nicolas horne

    hi, i don’t actually have any config questions, as i have four 8TB iron wolves laying around that i’ll start off with, and later probably just expand using the same drives. and i already have two super fast thunderblade and envoy drives for caching.
    but how is its fan noise levels?

  • Jon Elurra

    Hi Joey

    I’m interested on this Thunderbay as a content creator and filmmaker but I can’t find info about for some uses can offers this owc solution.

    I’m thinking to connect Flex via 10gbe to a 10gbe switch. Via thunderbolt will connect a Mac mini. And via 10gbe will connect a PC and a Raspberry Pi.

    Mac Mini will be a 1st way for editing video 4k with final cut and davinci (prores raw use directly of course). PC will use it for some editing works across 10gbe network, and Raspberry will be a NAS solution for backup and Wan connection frome my phone or a laptop and can do a copy of work via Wan with Open Media Vault.

    I don’t have yet this thunderbay because I want to be sure if it is possible my situation and my needed workflow, and I think this thunderbay flex is the better solution for me if I can do this setup with it.

    The principal dude is if I will can do it. Raid is across software, and don’t know if this will be posible, when the host thunderbolt is off, access thunderbay via RJ45 with Raspberry or PC across the router.

  • Joey D’Anna

    Hey Jon – unfortunately the Flex8 probably isn’t what you are looking for. It is a direct attach storage, not a network attached storage. You would need to connect it to a server and then share the RAID array from there.

    If you wanted to use it for a server (connected to a computer to share the volume) – you could use the pci-e slot to host a 10gbe network card though

  • Jeffrey Stevens

    Hi Joey

    I am struggling to understand the world of RAID, and would love to find a simple solution, even if it means spending some money.

    I create videos for online courses and YouTube. I work in 4k 10 bit from sony cameras.

    For a typical project, and I have a new one weekly, I work with about 100gb, sometimes more.

    I used to have no trouble just working off my 2tb internal drive on my MBP 16, but then I needed to offload for storage so got a Synology NAS with 4x6tb Iron Wolf drives.

    What I didn’t realize is that the NAS was far too slow to serve as something to transfer data back and forth quickly, and certainly too slow to work from.

    Well, now I am interested in the Flex8. But I don’t understand the product page very well.

    I want:

    1. a SSD pool of at least 4tb that I can work at SSD speeds connected to my MBP. I don’t know what U.2 is, but it sounds like it is fast.

    2. The SSD pool connecting into a backup solution that can absorb everything in the SSD pool and keep it backed up with redundancy (which seems like what people use RAID5 for). So, SSD data into spinning disk pool.

    3. If this exchange can be automatic, where the RAID on the spinning disks backs up the content on the SSDs, I would buy it immediately.

    I am thinking the top four bays could be SSDs, perhaps 4x 1tb, or maybe 4x2tb, and the rest spinning disks. I would use my Iron Wolf disks. Probably have to reformat them, right?

    In this configuration, are the SSDs a different RAID configuration than the spinning disks? Is it possible to have two configurations in one enclosure, a performance configuration for working on directly, and a backup configuration for keeping it all safe?

    Thanks for your knowledge and advice. There isn’t much I have found that makes this clear, and OWC didn’t even try to help me when I contacted them, they just pointed me to their product page.

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