StarTech.com

USB 3.0/eSATA Dual 3.5” SATA III Hard Drive External RAID Enclosure w/ UASP and Fan – Black

Create an external dual 3.5in HDD SATA RAID array, connected through either USB 3.0 with UASP or eSATA

Product ID: S3520BU33ER

  • UASP Support (Attached SCSI Protocol Specification Revision 1.0)
  • eSATA or USB Host Connection
  • Compatible with SATA revision I/II/III (1.5/3.0/6.0 Gbps)
View More
  • Hardware RAID
  • Plug-and-Play Compatible
  • Dual Drive Bay
  • Built-in Fan
£115.99 GBP exc VAT
£139.19 GBP inc VAT
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May be in stock with partners
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Overview

The S3520BU33ER 2-Bay RAID Enclosure offers a high-performance external storage solution, enabling you to build a secure RAID array with two 3.5” SATA hard drives, with the option to connect it to your computer through either an available USB 3.0 or eSATA port.

For fast data transfers and efficient performance from your SATA III drives, the RAID enclosure supports full SATA III transfer speeds (up to 6 Gbps), as well as full USB 3.0 transfer speeds (up to 5Gbps). When connected through USB, the enclosure supports UASP, which offers performance up to 70% faster than conventional USB 3.0 when paired with a UASP-enabled host controller (see our performance below).

With support for JBOD, Spanning, RAID 0, and RAID 1,the enclosure offers several options that enable you to customize your drive arrangement based on your storage requirements. 

To maximize both durability and reliability, the external RAID enclosure features high-quality aluminum construction with a built-in fan that helps improve ventilation and maintain a better operating environment for your drives.

The HDD enclosure offers a versatile solution for increasing the storage/backup capabilities of your computer, with support for large capacity hard drives (tested up to 4TB). 

To ensure compatibility with your computer system, the S3520BU33ER supports all of the leading operating systems, including: Microsoft Windows® (8/7/Vista/XP/Server 2008/Server 2003), Apple® OSX (10.9/10.8/10.7/10.6), Linux, and Google Chrome OS™.

It is backed by a StarTech.com 2-year warranty and free lifetime technical support.

Improved Performance with UASP

UASP is supported in Windows 8, Mac OSX (10.8 or above), and Linux. In testing UASP performs with a 70% faster read speed and 40% faster write speed over traditional USB 3.0 at peak performance.

UASP Speed Diagram

At the same peak in testing UASP also shows an 80% reduction in required processor resources.

UASP Speed Diagram

Testing results were obtained using an Intel® Ivy Bridge system, a UASP enabled StarTech.com Enclosure, and a SATA III solid state drive.

The StarTech.com Advantage

  • Versatile connectivity options, through either USB or eSATA
  • Time-saving file transfers, up to 70% faster than traditional USB 3.0 when used with a UASP-supported host
  • Achieve greater drive capacity or secure data redundancy with multiple RAID modes
  • Maximize performance, with file transfer speeds up to 6Gbps using SATA III

Applications

Business applications that require external RAID storage for data redundancy

Video editing or photography professional/enthusiasts working with very large file sizes

Transfer large files between computers quickly and securely without a network

Scenarios requiring easy storage transferability between different computer systems and large volume external storage for backups/archiving

Technical Specifications

Warranty Information
Warranty 2 Years
Hardware
Chipset ID JMicron - JMS562
Compatible Drive Types SATA
Drive Installation Fixed
Drive Size 3.5in
Fan Bearing Type Ball Bearing
Fan(s) Yes
Fans 1 - 40 mm
Interface eSATA
USB 3.0
Number of Drives 2
Number of internal 3.5 inch bays 2
Performance
Hot Swap Capability Yes
Max Drive Capacity Currently tested with up to 4TB 7200 RPM hard drive
Port Multiplier Yes
RAID Yes
Supported RAID Modes BIG (Spanning or Concatenation)
JBOD - (Just a Bunch of Disks)
RAID 0 (Striped Disks)
RAID 1 (Mirrored Disks)
Type and Rate USB 3.0 - 5 Gbit/s
SATA III (6 Gbps)
UASP Support Yes
Connector(s)
Drive Connectors SATA Data & Power Combo (7+15 pin) Receptacle
Host Connectors eSATA (7 pin, Data) Female
USB Type-B (9 pin) USB 3.0 Female
Software
Microsoft WHQL Certified Yes
OS Compatibility OS independent; No software or drivers required
Indicators
LED Indicators 1 - Enclosure Power LED
1 - Drive 1 Activity LED
1 - Drive 2 Activity LED
Power
Center Tip Polarity Positive
Input Voltage 100 ~ 240 AC
Output Current 3 A
Output Voltage 12 DC
Plug Type M
Power Consumption (In Watts) 36
Power Source AC Adapter Included
Environmental
Humidity 20%RH ~ 80%RH
Operating Temperature 5°C to 35°C (41°F to 95°F)
Storage Temperature -20°C to 50°C (-4°F to 122°F)
Physical Characteristics
Color Black
Enclosure Type Aluminum and Plastic
Product Height 85 mm [3.3 in]
Product Length 176 mm [6.9 in]
Product Weight 620 g [21.9 oz]
Product Width 113 mm [4.4 in]
Packaging Information
Shipping (Package) Weight 1355 g [47.8 oz]
What's in the Box
Included in Package 1 - USB 3.0/eSATA HDD RAID enclosure
1 - eSATA cable
1 - USB 3.0 cable
1 - universal power adapter (NA,EU,UK)
1 - rubber foot set
1 - instruction manual
Supports any operating system.
No additional drivers or software required.

Certifications

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Accessories

Product Support

Drivers & Downloads

Frequently Asked Questions

Before You Buy

To determine if your hard drive will work in this enclosure, on the product page, click the Technical Specifications tab, and do the following:

  • Make sure that the enclosure supports the storage size of your hard drive. If the storage size of your hard drive is larger than what the enclosure was tested with, the hard drive will likely still work with the enclosure.
  • Confirm that your hard drive uses the same interface type as the enclosure. For example, IDE, SATA, or M.2.
  • Make sure that the enclosure supports the physical size of your hard drive, such as 2.5 inches or 3.5 inches.
  • Make sure that the enclosure supports the height of your hard drive. For example, 9 mm or 15 mm.
  • Verify that the power consumption of your hard drive doesn’t exceed the power output of the enclosure. If you’re using multiple hard drives, make sure that the combined power consumption of all of the hard drives doesn’t exceed the power output of the enclosure.

Note: Not all StarTech.com devices support each of the RAID modes described below. For more information on the RAID modes that your device supports, refer to the manual or the StarTech.com product page.

Redundant Array of Independent Disks (RAID) is a virtual disk technology that combines multiple physical drives into one unit. RAID can create redundancy, improve performance, or do both.

RAID should not be considered a replacement for backing up your data. If critical data is going onto a RAID array, it should be backed up to another physical drive or logical set of drives.

The following are terms that are normally used in connection with RAID:

  • Striping: data is split between multiple disks.
  • Mirroring: data is mirrored between multiple disks.
  • Parity: also referred to as a checksum. Parity is a calculated value used to mathematically rebuild data.

Different RAID levels exist for different application requirements.

Refer to the following table for the list of RAID modes offered by some StarTech.com products:

RAID mode Description Operation Advantages Disadvantages Recovery
RAID 0 Striped disks Data is split evenly between two or more disks. Large size and the fastest speed. No redundancy. If one or more drives fails, this results in array failure.
RAID 1 Mirrored disks Two or more drives have identical data on them. A single drive failure will not result in data loss. Speed and size is limited by the slowest and smallest disk. Only one drive is needed for recovery.
RAID 3 Striped set with dedicated parity Data is split evenly between two or more disks, plus a dedicated drive for parity storage. High speeds for sequential read/write operations. Poor performance for multiple simultaneous instructions. A single drive failure will rebuild.
RAID 5 Striped disks with distributed parity Data is split evenly between three or more disks. Parity is split between disks. Large size, fast speed, and redundancy. The total array size is reduced by parity. A single drive failure will rebuild.
RAID 10 1+0; Striped set of Mirrored Subset Four or more drives are made into two mirrors that are striped. Larger size and higher speed than RAID-1, and more redundancy than RAID-0. No parity. Only one drive in a mirrored set can fail.
JBOD Just a Bunch Of Disks Any number of drives are accessed independently by the operating system. Software RAID modes can be used. Hardware RAID may have better performance. N/A
Big Spanning or Concatenation Data is written on one drive until it is full, and then the next drive(s) until it or they are full. Creates a very large and simple array.

No redundancy.

N/A
Clone RAID 1 + Spare

Two drives have identical data, plus one drive is used for rebuilding in case of a primary array failure.

Seamless operation when one drive fails in a RAID-1 array. Spare drive is not accessible to the user. Only one drive is needed for recovery.

 

How to

To confirm that the Mac OS detects your USB device, complete the following:

  1. Click the Apple icon.
  2. Click About This Mac.
  3. Click More Info or System Report.
  4. Under the appropriate heading, confirm that your USB device is listed and that there isn't an error. For example, a network card would be under Ethernet Cards.

You may need to refresh the System Information page after you plug in your device.  To do so, press Command R with the System Information page open.

Your USB device is listed according to the name of the chipset. To determine the name of the chipset of your USB device, navigate to www.StarTech.com and look on the Technical Specifications tab for your product.

Troubleshooting

SATA hard drive controllers require a feature called port multiplier to read more than one hard drive per SATA or eSATA port. The port multiplier feature is not standard on many SATA hard drive controllers.

If your computer is only recognizing one of your hard drives, you need to plug the eSATA cable into a SATA controller that includes the port multiplier feature. If none of your current hard drive controllers include this feature, you can add a hard drive controller that does support port multiplier in any available expansion slot (for example, PCI, PCI-Express, PCMCIA, CardBus, or ExpressCard). StarTech.com has hard drive controllers available that support the port multiplier feature. To view the hard drive controllers, click here: http://startech.com/Cards-Adapters/HDD-Controllers/SATA-Cards/?filter_PORTMULTIPLIER=Yes.

If you have a hard drive controller card that does support the port multiplier feature but it is only reading one hard drive at a time, update the drivers of the hard drive controller. To find the most current StarTech.com drivers, click here: http://www.startech.com/Support.

When you troubleshoot issues with a hard drive enclosure, there are some quick tests that you can complete to rule out potential problems. You can test to make sure that the following components are working correctly and are not the source of the issue:

  • Cables
  • Hard drives
  • Hard drive enclosure

To test your setup components, try the following:

  • Use the cables, hard drives, and hard drive enclosure in another setup to see if the problem is with the components or the setup.
  • Use a different cable, hard drive, and hard drive enclosure in your setup to see if the problem persists. Ideally, you should test a component that you know works in another setup.

When you test the hard drive and hard drive enclosure, it is recommended that you do the following:

  • To check Disk Management, press the Windows key + R, type diskmgmt.msc, and press Enter. Check to see if your hard drive is listed.
  • If the hard drive is listed with unallocated space, the hard drive needs to be reformatted. Right-click unallocated and click New Simple Volume. Follow the on-screen instructions to complete the reformatting.​

Note: Formatting a hard drive erases all of the data on it. Make sure that you back up all of your data before you reformat the hard drive.​

  • If the hard drive is listed as healthy but does not have a drive letter, for example, C:, right-click healthy and click Change Drive Letter and Paths. Click Add, assign a drive letter, and click OK.

Note: A formatted hard drive will not show up in Computer or My Computer until it has a drive letter assigned to it.

Note: Any data currently on the drives will be lost during this process. You need to back up all of your data before you set a RAID mode.

To set a RAID mode, complete the following:

  1. Use a USB cable to connect the hard drive enclosure to a computer.

Note: Your computer needs to be turned on while completing these instructions.

  1. Turn off the hard drive enclosure.
  2. Set the RAID switch to the RAID mode that you want to set.
  3. Press and hold the Set button and turn on the hard drive enclosure.
  4. When the enclosure is turned on, release the Set button.

Note: When you change the RAID mode again, complete the steps above to set the unit back to JBOD before you set a different RAID mode.

In order to rebuild a RAID array, you need to replace a physical drive with an identical drive on the same RAID controller. Although standard RAID levels are generally agreed upon throughout the industry, the implementation varies between manufacturers. RAID arrays are typically not accessible when they are moved to another controller, and data may be unrecoverable if the drives are out of order or have been formatted or accessed by another RAID controller.

If a RAID controller has failed, you should get the exact same model of RAID controller.  

Note: If a drive or drives were damaged, it is possible that the RAID array may be permanently unrecoverable.

RAID should not be considered a replacement for backing up your data. If critical data is going onto a RAID array, you should back up the data on another physical drive or logical set of drives.

Rebuild a RAID array

With the following RAID modes, recovery is possible using the same StarTech.com product. Refer to the following table for the appropriate method to use to recover your RAID array.

RAID mode Max # of failed drives Procedure
RAID 1 Only one drive is needed for recovery.
  1. Determine which drive is operational by using the RAID management utility (if available) or test each drive individually on a different hard drive controller (for example, a hard drive docking station or SATA controller).

  2. Replace the failed drive with an identical hard drive.

The array will rebuild and is accessible during the rebuilding process.

RAID 3 Single drive failure will rebuild.
  1. Determine which drive is defective by using the RAID management utility (if available) or with diagnosis LEDs on the controller or enclosure.

  2. Replace with an identical hard drive.

Note: Do not change the order of the drives.

  1. The array may be accessible during the rebuild, but you should let the controller rebuild without interruption so that performance is not compromised.

RAID 5 Single drive failure will rebuild.
  1. Determine which drive is defective by using the RAID management utility (if available) or with diagnosis LEDs on the controller or enclosure.

  2. Replace with an identical hard drive.

Note: Do not change the order of the drives.

  1. The array may be accessible during the rebuild, but you should let the controller rebuild without interruption so that performance is not compromised.

RAID 10 Only one drive in a mirrored set can fail.
  1. Determine which drive is defective by using the RAID management utility (if available) or with diagnosis LEDs on the controller or enclosure.

  2. Replace with an identical hard drive.

Note: Do not change the order of the drives.

  1. The array may be accessible during the rebuild, but you should let the controller rebuild without interruption so that performance is not compromised.

 

You should not upgrade your device's firmware if you do not have any issues with the functionality of your device. The only time you should consider an upgrade is if you are experiencing a problem with the device, and you have confirmed that the firmware addresses this problem.  You can confirm this is the case by reviewing the documentation included with the firmware or by consulting with our Technical Support team. Incorrectly upgrading firmware can result in diminished performance so it is best to contact StarTech.com if you would like to perform this operation.

USB 3.0/eSATA Dual 3.5” SATA III Hard Drive External RAID Enclosure w/ UASP and Fan – Black

Customer Reviews

2 (1 reviews)
2 out of 5 stars
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1 - 1 of 1 Reviews

(2 stars) Good speed when it's not disconnecting

By:
Seemed to work well but disconnects from the computer (Windows 10) once a day or more (and you then need to power cycle it to reconnect). Finally one of my drives was reporting errors so I tried moving data to another drive on the computer itself. It was a 6GB drive and the during the transfer it kept disconnecting until I finally got fed up and removed the drive from the enclosure. Put it in a different brand enclosure and the transfer is going well now. I may try to upgrade the firmware, but the download doesn't have any details about what's been fixed, and basically I don't trust this enclosure anymore.
Comment Helpful? Yes - 0 No - 1 Report
Response from StarTech.com:
Malcolm, Customer Support
Thanks for taking the time to leave your feedback. We apologize our S3520BU33ER seems to be causing intermittent issues in your setup, and want to help. The firmware just corrects a bug related to how the enclosure is labeled in Device Manager in various RAID modes. It doesn't affect actual unit functionality. The enclosure has a 2 year warranty and free lifetime technical support. Please chat with us at https://chat.startech.com so can troubleshoot and potentially help you get the dock replaced if needed.
By: jlmedina
Same issue With windows 10 and USB3. eSATA works fine... Har disk tested with another USB3toSATA adapter and performs fine.
Helpful? Yes - 0 No - 0 Report