You're looking for a way to back up your files automatically without a cloud subscription, or you want to combine more storage than a single SSD offers. That's when you come across the term "RAID enclosure" or "dual bay": an enclosure with two drive bays instead of one. This article explains what that means in practice, what your options are, and when two SSDs are genuinely smarter than one.
What is a RAID enclosure (dual bay)?
A dual-bay enclosure has two slots for M.2 SSDs, which connect to your computer through one single USB connection. A hardware switch on the enclosure itself lets you set how the two SSDs work together (no software, no computer needed for the setup). On the Switss RAID Dual-Bay, this is done with dip switches on the inside and a confirmation button; LEDs on the front show which mode is active.
The four modes at a glance
| Mode | What it does | Available capacity | Risk if a drive fails |
|---|---|---|---|
| RAID 0 (Striping) | Spreads files across both SSDs; works as one super-fast drive | Full combined capacity | High: if one SSD fails, you lose all data on both drives |
| RAID 1 (Mirroring) | Writes every file to both SSDs at the same time | Half of the total capacity | Low: your data stays safe on the other SSD |
| JBOD | Both SSDs work as two separate, independent drives | Full capacity of both, separately | Only the affected SSD loses data |
| Clone | Copies the contents of SSD A to SSD B at the press of a button, even without a computer connected | Equal to the source size | N/A (it's a backup copy itself) |
If you switch modes, both SSDs are reinitialised and all existing data is lost. So make a backup on another drive first before switching. For the technical background on RAID 0 versus RAID 1 (why one gives you speed and the other gives you safety), you'll find a full explanation in RAID 0 vs RAID 1 Explained: Speed or Safety?
Why two SSDs are smarter than one
A single M.2 enclosure with one SSD slot works fine as extra storage, but it offers no safety net: if the drive fails, you lose the data, unless you manually keep a second copy yourself. A dual-bay enclosure solves that automatically:
- Automatic backup without a cloud subscription. In RAID 1, the enclosure writes every file to both SSDs at the same time. No monthly costs, no internet connection needed.
- Combined capacity or speed. In RAID 0, both SSDs work together as one drive, with combined capacity and higher speed (useful for large photo and video libraries).
- Two separate drives, one cable. In JBOD mode, you keep two independent drives on a single USB connection, handy if you simply want more storage space without RAID risks.
- Making a backup copy without a computer. Clone mode duplicates a drive at the press of a button.
If you only have one M.2 SSD and automatic backup isn't a priority, a single M.2 enclosure with heatsink is cheaper and simpler. Still unsure between an M.2, 2.5-inch or 3.5-inch enclosure in general? Which enclosure do I need for my old hard drive? will help you decide.
Speed: what can you expect in practice
The Switss RAID Dual-Bay connects via USB-C 3.2 Gen 2, up to 20 Gbps: double the 10 Gbps a single M.2 enclosure reaches. Actual speed depends on your SSDs, the mode you choose and your computer's USB port: on an older USB 3.0 port (5 Gbps) speed drops, and NVMe SSDs are faster than SATA M.2 SSDs. Want the theory behind Gbps versus MB/s and how USB4 compares? That's covered in Thunderbolt 4 vs USB4 vs USB 3.2: Speeds Compared.
Which M.2 SSDs fit, and how much storage can you use
The enclosure works with M.2 NVMe and M.2 SATA SSDs, with an M-key or M+B-key connector, in the 2230, 2242, 2260 and 2280 formats. Every brand and every capacity is compatible. Not sure yet which type of SSD you have or want to buy? Read NVMe vs SATA M.2 SSD: what's the difference (and what do you need)?
Without external power, the enclosure supports SSDs up to 2× 2 TB. Connect a 5V/3A USB-C charger, and that goes up to 2× 8 TB.
Setting it up without software: how does that work?
You set the mode on the inside of the enclosure with dip switches, then hold the confirmation button for a few seconds until the LEDs flash. So the LEDs on the front aren't buttons; they're an indicator of the active mode (the factory setting is called "PM" on the product page: both SSDs as separate drives). No PC, no app, no driver needed for the setup itself. One important thing: always save your files somewhere else first before switching modes, because the SSDs are reinitialised in the process.
The aluminium enclosure with thermal pads on both SSD slots dissipates heat, keeping both drives at a stable temperature even during long copying or streaming sessions.
In the box
- Switss RAID Dual-Bay M.2 SSD enclosure
- USB-C to USB-C cable
- Screws and screwdriver for M.2 installation
- Quick start guide
The enclosure ships without SSDs and without a power cable: you click in your own M.2 SSDs (SSDs above 2 TB each need their own 5V/3A USB-C charger).
Frequently asked questions
Does the RAID enclosure come with SSDs?
No. You fit your own M.2 NVMe or SATA SSDs; every brand and every capacity up to 2× 8 TB (with external power) is compatible.
Do I lose my files if I switch RAID mode?
Yes. When you switch, the SSDs are reinitialised and all existing data is lost. Back up to another drive first.
Which M.2 SSDs fit inside?
NVMe and SATA, with an M-key or M+B-key connector, in the 2230, 2242, 2260 and 2280 formats. Regular 2.5-inch SATA drives or 3.5-inch hard drives don't fit.
How fast is the transfer speed?
Up to 20 Gbps via USB-C 3.2 Gen 2, depending on your SSDs, the mode you choose and your computer's port.
How much warranty do I get?
2-year manufacturer's warranty, with Dutch customer service.
Next step
Want your files automatically saved twice, or want to combine the capacity of two SSDs without a cloud subscription? Check the specifications and current price on the product page: Switss RAID Dual-Bay M.2 SSD enclosure. If you only have one SSD, check out the M.2 SSD enclosure with heatsink as a simpler, cheaper alternative.
