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OWC ThunderBay 4 mini
RAID 5 Edition

Portable 4-bay Professional-Grade Enclosure

Dual Thunderbolt 2 | RAID 5 | 4 Drive Bays | Mac
Performance + Redundancy
Experience the first and only software RAID 5 technology developed for the Mac with the ThunderBay 4 mini RAID 5 Edition. With a compact design optimized for 2.5" drives, ThunderBay 4 mini RAID 5 Edition delivers outstanding performance and reliability for the most demanding applications, including workflows involving 4K, 2K, uncompressed HD, and multi-stream SD video.
  • Up to 1010MB/s read / 908MB/s write sustained RAID 5 performance*
  • Up to 1346MB/s read / 1321MB/s write sustained RAID 0 performance*
  • Preconfigured in RAID 5 for optimal data redundancy
  • 75% faster rebuild times than hardware RAID

  • Do more with a ThunderBay enhanced workflow.
    Expand production capabilities for industry-leading creative platforms like Final Cut X, Avid Pro Tools, and Adobe Lightroom with this incredibly fast and portable 4-bay storage solution. The ThunderBay 4 mini RAID 5 Edition Enclosure Kit includes SoftRAID 5 for ThunderBay, an incredibly robust software RAID engine that supports RAID 0, 1, 4, 5, and 1+0 arrays. Add your choice of up to four 2.5" hard drives, SSDs, or a mix of both to achieve the optimal balance of storage, performance, and data-redundancy your workflow demands.
    The RAID 5 Advantage
    With RAID 5, the four drives inside ThunderBay 4 mini are merged for increased capacity and tremendous performance gains over a single drive. Special redundancy data, called "parity information," is also stored across the drives, allowing your data to remain completely safe so you can maintain your mission critical workflows worry-free.
    Thinking Outside the Enclosure
    OWC unlocks the incredible performance and flexibility of ThunderBay by pairing the drives with a robust software RAID solution. Powered by the SoftRAID engine, ThunderBay 4 mini RAID 5 Edition delivers advanced RAID modes, real-time health monitoring with email notifications, and best-in-class rebuild speeds. Unlike traditional software RAID solutions, SoftRAID 5 for ThunderBay's revolutionary volume optimization allows you to quickly configure your drive for specific workflows. Now, you can experience the absolute best performance whether recording audio, editing 4K video, or creating a multimedia server.
    Flexible and Robust
    Take full advantage of the flexibility offered by the ThunderBay 4 mini and SoftRAID engine. Easily build and reconfigure complex RAID arrays, or connect multiple ThunderBays to create even larger RAIDs with up to 16 drives for optimal performance and redundancy. Now, users can enjoy robust RAID options with near enterprise-grade storage and performance for a fraction of the cost.

    4 drive bays plus so much more.
    Time-tested Cooling Cool + Whisper Quiet
    A durable, heat-dissipating, aluminum unibody shell features a "flow-thru" vented design coupled with a 60 mm whisper-quiet fan.
    DisplayPort 1.2 4K Display Support
    Dual Thunderbolt 2 ports let you connect any display that your computer can support, including 4K displays.
    Vibration Dampened Vibration Dampened
    ThunderBay's drive isolating design reduces sonic resonance, and is aided by rugged, vibration-absorbing, non-skid feet.
    Multi-Drive Flexible Expansion
    Daisy-chain up to six ThunderBays on a single Thunderbolt port for expansive storage, RAID, and performance options.
    Thunderbolt Cable OWC Thunderbolt Cable
    ThunderBay comes with an OWC one-meter certified Thunderbolt cable, with other lengths from 0.5 meter to 30 meters available separately.
    *Speed dependent on drive mechanism used


    • OWC ThunderBay 4 mini High-performance 4-bay Thunderbolt 2 interface drive
    • SoftRAID 5 for ThunderBay
    • High-Quality, Certified, Double-Shielded 1-Meter Thunderbolt cable
    • External UL listed 3-prong power cable
    • 2 keys for front panel lock
    • ThunderBay 4 mini Quick Start Guide
    • OWC ThunderBay 4 mini Assembly Manual & User Guide (Download Only)
    • Utility software bundle for Mac
    • 1 Year OWC Enclosure Limited Warranty


    Product Specifications

    Mechanisms Supported

    • Four 2.5" 15mm SATA 6Gb/s drives


    • Thunderbolt 2

    Interfaces Supported

    • Thunderbolt 2

    JBOD / RAID Support

    • JBOD: Utilize each of the four drives independently
    • RAID: Use the included software RAID or one of your choice to setup the ThunderBay 4 for multi-drive performance or data redundancy.
    • SoftRAID 5 Support Page

    Port Configuration

    • Thunderbolt – (2) Thunderbolt 2 ports

    Max Data Transfer Rate

    • Thunderbolt 2 – 20Gb/sec

    Port/Interface Bootability

    • It can be used as a Thunderbolt startup drive on Macs running Mac OS X.

    System Requirements

    • Any Mac with a Thunderbolt port running OS X 10.9 or later.
    • Boot Camp is not supported. The Thunderbolt certification process does not include Macs running Windows through Boot Camp.

    Power Supply

    • UL Listed U.S./International Auto Switching 100 ~ 240v, 50/60Hz input, 12 Volt 6.0 Amp output Power Supply (power cords for International use sold separately).

    Software Included

    External Case Dimensions

    • 7.6"(D) x 3.8"(W) x 4.6"(H)
    • 19.3cm x 9.6cm x 11.6cm

    Enclosure Weight (no accessories)

    • Approximately 2.4 pounds (1.1kg)

    Product Manual

    Operating Environment:


    • (operating) 5°C – 42°C (41°F – 107°F)
    • (non-operating) -40°C – 65°C (-40°F – 149°F)

    Relative Humidity

    • (operating) 8% – 90% RH (Non-condensing)
    • (non-operating) 5% – 95% RH (Non-condensing)


    • 65G 2mS; (non-operating) 175G 2mS


    • (operating) 1.0G (5 – 300Hz)
    • (non-operating) 5.0G (5 – 500Hz)


    1 Year OWC Enclosure Limited Warranty

    The best warranty is one you never have to use, but should the need occur - OWC is proud to provide a superior level of support and warranty coverage to our customers. Even when not used, we understand the peace of mind afforded by a longer warranty period. OWC's industry leading coverage is a testament to our confidence in the reliability of the solutions that we offer. OWC solutions are engineered to demanding quality standards in order to deliver the most reliable, highest performance available on the market in each storage category.

    View more information about the 1 Year OWC Enclosure Limited Warranty

    Note: Do not disassemble or otherwise open your OWC solution prior to the conclusion of the 1 Year OWC Enclosure Limited Warranty period. Doing so will void the remainder of the OWC warranty.

    Manufacturer provided specifications for Other World Computing p/n TB4MSR0GB UPC#: 812437021073


    SoftRAID 5 for ThunderBay
    OWC has partnered with SoftRAID to bring software RAID 5 to the Mac. SoftRAID combines advanced RAID modes, fast performance, monitoring, e-mail notification, and fast rebuild capabilities that only software RAID can deliver. ThunderBay 4 models with drives come preconfigured in RAID 5, and are plug and play ready with OS X 10.9 or later. Advanced features such as drive notification and monitoring require SoftRAID installation.


    Customer Ratings

    Write a Review 4.5 / 5 8 out of 9 (89%) reviewers would recommend this product
    Verified Buyer
    Reviewer: Loby1
    Rating: 5/5 Great Product - Very Quiet! October 17, 2017 Very quiet which was the main reason I selected this unit over other manufacturers. I was using another thunderbolt unit from another company...but the fan and airflow through the other company's unit made too much noise for my taste. I use SSDs that do not require much cooling as does HDDs, so this unit is perfect for me (though HDDs would work well also with the unit), I work with Video and Audio recording using a Mac Pro 2013, so the ThunderBay 4 mini is perfect for the cost and my usage! Highly recommend it!

    I would recommend this item to a friend! Customer Videos:

    Verified Buyer
    Reviewer: JohnnyW Location: New Orleans, LA Age: 45-54 Experience Level: IT Professional Owned Product: less than a month
    Rating: 5/5 Perfect July 25, 2017 I have been re-configuring my home network and going through the hardware I had laying around and found a bunch of 2.5" drives. So to re-purpose them, I ordered the OWC Thunderbay 4 Mini. I knew it was going to be the perfect piece of hardware I needed for these drives as I have been a loooong time & satisfied OWC customer and have been ordering all my MAC upgrades from them.

    I was quite surprised at the small form factor, sleek looks, and very fast performance. The Thunderbay was easy to load the drives into and it was plug & play to connect to my Mac Mini.

    I would recommend this item to a friend! Customer Videos:

    Verified Buyer Top 250 Contributor
    Reviewer: HenryInFlorida Location: Florida, USA Age: Over 65 Experience Level: IT Professional Owned Product: 1-3 months
    Rating: 4/5 Thunderbay 4 + SoftRAID hits the spot for MacBook Pro External Media March 12, 2017 I got this product from OWC (Thunderbay 4 mini drive enclosure 0 drive) as a solution to accommodate a number of (new) SSD's into my external drive plan with a single cable as a DAS for fast external access to my photography raw files. I wanted a device that would be capable of very fast throughput for fast read/write performance supporting the fastest transfer rates but also compatible with both what I have now (MBP 2014) and the future machine I hope to get in the next year (2016+ MBP). A singe drive measures over 300Mbps read/write speed, while the RAID 4 array measures 730 Mbps Read and 1,004 Mbps read using AJA System Test Lite and Blackmagic DiskSpeed benchmarks. That is fast enough for most formats of video on my MBP. Your speeds will definitely vary with source machines, drives, and connection methods.

    Works on all counts. I can't say enough about the support I got from SoftRAID pre and post sale. I had lot of configuration questions and expectations on configuring the internal four drives and using it as a RAID array with additional partitioning of a drive larger than others.

    First, about the OWC Thunderbay's mechanical assembly. It is a very sturdy black painted aluminum case. It stand on four rubber feet and is very quiet when the fan runs, it is practically inaudible in a quiet room. On the front you have a keyed lock, LED's on the front for power, drive access (4) and ventilation holes for the fan powered assembly.

    The front panel completely removes with the key. It removes exposing four drive trays that simply plug in to the rear frame. The front panel secures the drives from becoming disconnected with an integral bumper strip.The drives can "hot-swap", however in the case of a RAID array, that will be rather ineffective to yiour operation if a drive is removed for any other reason than replacing it with the same size and rebuilding an array. If you will use the enclosure to house media as formatted as JBOD then hot swap will work for you, just be sure to dismount the drive before removing. The system will need to be reattached to T2 port to mount on your host computer or re-powered. I usually disconnect the power plug after ejecting the drives. Therefore, this hot-swap feature isn't needed and no power switch is provided.

    At the rear, you'll find a 72W DC power connection jack requiring the supplied external power pack, two Thunderbolt 2 jacks used to loop between other devices (multiple drives, monitors, etc. Note that this enclosure is Thunderbolt 2 (20Gbps) and is only downward compatible with Thunderbolt 3 (40Gbps).

    The drive trays are metal and well grounded to the case for static control. Your drives screw to the tray with four screws each and are supplied. Spares are available but only as a set.

    The overall documentation and product quality is very good. This is a good value for the product provided.

    I give it a 4 star rating based on my list of pros and cons below. This is a user's review not paid or in any way compensated by the distributor. Would recommend!

    I would recommend this item to a friend! Customer Videos:

    Verified Buyer
    Reviewer: Gamma Location: Washington State Age: Over 65 Experience Level: Power User Owned Product: less than a month
    Rating: 5/5 No more beachballs December 16, 2016 With 2.5 million MRI files on a conventional disk using Firewire 800, the repeated seek delays were beyond annoying, despite using a 2013 MacPro and the latest OsirixMD. This hardware has fixed the issue nicely and reduces any worry about data reliability. No beachballs.

    This review is from 4.0TB OWC ThunderBay 4 mini, four-drive SSD with dual Thunderbolt 2 ports, RAID 5 Solution. Customer Videos:

    Verified Buyer
    Reviewer: Foxy Location: Springfield, MO Age: 55-65 Experience Level: Home User Owned Product: 1-3 months
    Rating: 5/5 Small sized equals big storage July 23, 2016 This review is from (*) OWC ThunderBay 4 mini, four-bay drive enclosure with dual Thunderbolt 2 ports, RAID 5 *R*.
    Verified Buyer
    Reviewer: Anonymous Location: Fort Worth, Texas Age: Over 65 Experience Level: IT Professional Owned Product: 1-3 months
    Rating: 5/5 Exceeds all expectations May 26, 2016 For years I have dreamed of having a RAID 5 array for speed and reliability. This fills the bill nicely and its performance exceeds all my expectations. With 7200 RPM HDs the performance easily exceeds the other external drives I have and although I have not had the "opportunity" to test the RAID 5 data recovery capability, I am confident it will perform as advertised.

    I would recommend this item to a friend!

    Verified Buyer
    Reviewer: Anonymous Location: Los Angeles Age: 55-65 Experience Level: Power User Owned Product: 1-3 months
    Rating: 5/5 Fast! May 11, 2016 This thing is beastly fast! Throws 4K files around like they're nothing! Very Quiet too! Two thumbs up!

    I would recommend this item to a friend! This review is from 4.0TB OWC ThunderBay 4 mini, four-drive SSD with dual Thunderbolt 2 ports, RAID 5 Solution.

    Verified Buyer
    Reviewer: Anonymous Location: West Haven, CT Age: 45-54 Experience Level: Power User Owned Product: 1-3 months
    Rating: 5/5 Great enclosure November 16, 2015 As a working photographer, I'm always on the lookout for faster, quieter storage for terrabytes of data. An all-SSD 4TB RAID 5 setup is still beyond my ability to rationalize, but I recently got the crazy idea to go the Fusion Drive route instead, and it's working beautifully thus far.

    I picked up the Thunderbay 4 mini, popped in two 2TB Seagate 2.5" drives and a 480GB SSD and, bar a small setup issue (hint to others: there's no need to buy the RAID5 version of the enclosure if you're going the Fusion Drive route, as SoftRAID won't work with that setup), it has performed exactly as expected. Performance with newly-downloaded photos is lightning-fast, since they get copied to the SSD portion of the Fusion Drive, and if I have to go back to some older data for a job, it usually gets moved to the SSD after a few accesses. My Lightroom catalogs also reside on the SSD pretty much permanently, given how ofter they're accessed. The access lights on the Thunderbay are very helpful in determining which drives are being accessed at any given time.

    I'm sure that most will be purchasing this enclosure to create a more standard RAID volume, but I wanted to let prospective purchasers know that it works quite well in a non-standard setup. It was an idea I'd had in my head for a while, and I'm glad I finally pulled the trigger - it has lived up to my expectations, and I wouldn't hesitate to recommend something similar to anyone looking for a brilliant combination of fast access and copious storage in a small, quiet (though not silient) package.

    I would recommend this item to a friend!

    Verified Buyer
    Reviewer: Anonymous
    Rating: 5/5 Great value enclosure. October 12, 2015 Fully loaded with Samsung Pro SSDs, I can verify read speed over 1GB/s using the included SoftRAID driver over a Thunderbolt 2 connection to a Mac Mini.

    The enclosure itself is fantastic. I'll ding SoftRAID slightly for not having a driver for El Capitan ready at launch, but the current beta driver has been working fine. This isn't a fault of the enclosure itself, though, and the enclosure works fine with SoftRAID if you want to stick with the standard Apple drivers.

    I would recommend this item to a friend!

    Verified Buyer
    Reviewer: Anonymous Location: Tokyo, JP Age: 35-44 Experience Level: IT Professional Owned Product: less than a month
    Rating: 4/5 Good performance for the price. October 10, 2015 I like the ThunderBay 4 Mini SSD RAID box. It is a lot of storage in a small package. The software made it really easy to setup everything. I was able to easily chain in a monitor in TDM. The major benefit with the mini is the power unit is external and that heat is not in the enclosure and it is all very small. The fan is not as "whisper-quiet" as advertised, but it is fairly quiet. If one of your reasons for using SSDs is to avoid noise, the fan might bother you. The overall benefit of the RAID enclosure far outweighs the small noise issues.

    Write speeds for four drives in RAID 10 (1+0) were slightly faster than two original Mac SM256E SSDs in RAID 1. Read speeds were about the same with double the drives, but it is still fast enough for my needs so no real complaint about it.

    I would recommend this item to a friend! This review is from 2.0TB OWC ThunderBay 4 mini, four-drive SSD with dual Thunderbolt 2 ports, RAID 5 Solution.

    Verified Buyer
    Reviewer: Anonymous Location: Switzerland Age: 35-44 Experience Level: IT Professional Owned Product: 1-3 months
    Rating: 4/5 Fast and sturdy, but not silent September 11, 2015 I'm running four SSDs (Samsung SSD 840 EVO Basic 1 TB) inside my ThunderBay mini, which is connected to a 5K iMac, with an OpenZFS RAID-Z over all drives.

    While the enclosure is sturdy and transfers are fast, I'm a bit disappointed about the fan noise. Its fan is rather small, and as such has to spin fast to generate a respectable air flow.

    I could disconnect the fan, but I'd most likely lose warranty and would worry about temperatures (though I suspect that in my environment and with SSDs rather than HDDs it might be OK).

    Because of the noise there are times I want to switch the unit off, and because it has no power switch one has to disconnect the Thunderbolt cable to do so.

    For comparison: I used to have one of OWCs bigger enclosures (for four 3.5" drives; with eSATA, Firewire 800 and USB 2 connectors), which also had some fan noise, however its larger fan would spin slower, generating less noise that could more easily be ignored.

    So if you care about noise a lot I'd suggest thinking about this enclosure's bigger sibling, even though it "wastes" a lot of space if you use 2.5" drives with it.

    I would recommend this item to a friend!

    Verified Buyer
    Reviewer: Anonymous Location: Ardmore pa Age: 35-44 Experience Level: IT Professional Owned Product: 1-3 months
    Rating: 5/5 Great storage solution May 14, 2015 I'm an it guy. This was an inexpensive enterprise grade raid solution for a consumer price. I went with Speed and storage and used 7200 rpm laptop drives. This replaced my LaCie jbod storage. My storage performance went from 70mb per second to about 400mb not as fast as my 900mb raid0 ssd os solution but getting 3tb with the read rate it's worth it. SoftRaid 5 works great. And was worth the extra cost. Looking forward to grabbing an additional one of these storage arrays soon.

    I would recommend this item to a friend!

    Verified Buyer
    Reviewer: Anonymous
    Rating: 3/5 Great size efficiency and overall solution mitigated by little annoyances May 3, 2015 My desk doesn't have a lot of available space, so the ThunderBay 4 mini seemed like a good fit (literally). It's small, fast, accommodates 4 drives and it is optimized for SSDs -- doesn't waste precious volume on accommodating 3.5" form factors. It's metal and feels rock-solid. Comes with a Thunderbolt cable. Works great, and the version with SoftRAID rounds it out for a great RAID 4/5 solution. I liked it a lot, at least until I powered it up.

    The downsides are that you end up with an power brick -- I hate external transformers -- and that small fan that all the reviews and product information say is "quiet" really isn't if you have silent SSDs (like the Mercury Electra 6Gs that I also purchased) in it. You have audible low frequencies of air passing through the enclosure. Those don't bother me. However, the MB60201V3-0000-A99 fan (in theory, 23 dBA from OEM spec sheet) used in the enclosure has this soft, high-pitched whine that was distracting to both me and the other occupant of the room it lived in. As much as I'd like to keep it, that's a dealbreaker for it to be used where I need to.

    Return RMA is underway, and I'm looking at the full-size ThunderBay 4 RAID edition as a replacement with its lower-RPM fan (20-23 dBA) and internal power supply, as well as its unfortunately much larger size and need to use 3.5"-to-2.5" step-down carriers for my SSDs.

    OWC ThunderBay 4 mini - RAID 5 Edition Enclosure Mfr P/N: TB4MSR0GB OWC SKU: OWCTB4MSR0GB High-Performance 4-bay External Drive 1 Year OWC Enclosure Limited Warranty
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