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
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.
At the same peak in testing UASP also shows an 80% reduction in required processor resources.
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
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
|Ingram Micro España||V932998|
|Chipset ID||JMicron - JMS562|
|Compatible Drive Types||SATA|
|Fan Bearing Type||Ball Bearing|
|Fans||1 - 40 mm|
|Number of Drives||2|
|Number of internal 3.5 inch bays||2|
|Hot Swap Capability||Yes|
|Max Drive Capacity||Currently tested with up to 4TB 7200 RPM hard drive|
|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)|
|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|
|Microsoft WHQL Certified||Yes|
|OS Compatibility||OS independent; No software or drivers required|
|LED Indicators||1 - Enclosure Power LED|
|1 - Drive 1 Activity LED|
|1 - Drive 2 Activity LED|
|Center Tip Polarity||Positive|
|Input Voltage||100 ~ 240 AC|
|Output Current||3 A|
|Output Voltage||12 DC|
|Power Consumption (In Watts)||36|
|Power Source||AC Adapter Included|
|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)|
|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]|
|Shipping (Package) Weight||1.4 kg [3 lb]|
|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|
Add four 3.5" SATA III hard drives to your computer externally through USB 3.0 with UASP or eSATA
Turn four 3.5” SATA/SAS drives into a 1U rack-mountable storage solution with external Mini SAS connectivity
Replace your lost or failed power adapter
Connect your external SATA storage devices to your Laptop or desktop.
Turn a standard SATA motherboard connection into an external eSATA port
Connect your USB 3.0 devices with this high-quality USB 3.0 certified cable
Connect your USB 3.0 devices, with this high-quality USB 3.0 certified cable
Connect USB 3.0 devices, even in hard to reach areas and tight spaces
Connect USB 3.0 devices, even in hard to reach areas and tight spaces
Add 4 external USB 3.0 ports to a low profile or standard computer, through PCI Express
Add Two eSATA 3.0 (6Gbps) Ports for High Speed Access to Large External Storage Solutions
Add 2 external or internal SATA 6 Gbps ports to a computer, through a PCI Express slot
Add external and internal 6 Gbps SATA 3.0 ports for high speed storage access
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 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.||
|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.|
To confirm that the Mac OS detects your USB device, complete the following:
- Click the Apple icon.
- Click About This Mac.
- Click More Info or System Report.
- 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.
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:
- 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:
- 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.
- Turn off the hard drive enclosure.
- Set the RAID switch to the RAID mode that you want to set.
- Press and hold the Set button and turn on the hard drive enclosure.
- 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.||
The array will rebuild and is accessible during the rebuilding process.
|RAID 3||Single drive failure will rebuild.||
Note: Do not change the order of the drives.
|RAID 5||Single drive failure will rebuild.||
Note: Do not change the order of the drives.
|RAID 10||Only one drive in a mirrored set can fail.||
Note: Do not change the order of the drives.
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.
Compliance and Safety
- If product has an exposed circuit board, do not touch the product under power.
- If Class 1 Laser Product. Laser radiation is present when the system is open.
- Wiring terminations should not be made with the product and/or electric lines under power.
- Product installation and/or mounting should be completed by a certified professional as per the local safety and building code guidelines.
- Cables (including power and charging cables) should be placed and routed to avoid creating electric, tripping or safety hazards.
* Product appearance and specifications are subject to change without notice.