RAID (Redundant Array of Independent Disks) combines multiple physical drives into one logical storage unit. The chosen RAID level determines how data is arranged across those drives—and whether the array prioritizes capacity, performance, or protection against certain drive failures.
What does RAID mean?
RAID stands for Redundant Array of Independent Disks. Seagate defines it as a system that “combines multiple physical drives into one logical storage unit (an array)” in its RAID Manager User Manual – RAID Concepts and Terminology.
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RAID is not a single layout. It is a way to organize several drives, and the RAID level specifies how data is distributed or duplicated. As a result, the word “redundant” does not describe every level: RAID 0, for example, has no redundancy.
How does RAID arrange data?
Striping
Striping splits data into pieces and distributes them across multiple drives. This can support parallel access, but striping alone does not create a duplicate copy or provide protection from a drive failure.
#1 Best Overall
- Note:The eSATA port on this product does not support the use of a computer’s SATA-to-eSATA adapter. Hot-swapping is not supported. The computer’s eSATA port must support RAID functionality to properly access multiple drive bays via the eSATA port; otherwise, only one drive bay can be accessed.
- 【Reliable External Storage System for Individuals】The 3.5 hard drive enclosure supports 2.5/3.5 inches HDD and SSD , max capacity up to 80TB( 20TB for each hard drive), it's a ideal external hard drive enclosure for personal or enterprise using.Save space on your desktop or laptop.
- 【No heat,】The 4 bay hard drive reader built in Aluminum-Alloy materials and 2 inch Fans.Maximize the security of your data.NOTE：Fan noise is around 40-50 decibels, not recommended if you are very sensitive to noise.
- 【8 Raid Modes】This external hdd raid enclosure supports RAID 0/1/3/5/10, CLONE, LARGE, NORMAL.NOTE:When replacing RAID, you need to go back to NORMAL and set the desired RAID mode.Designing RAID may result in data loss.MAC OS no Raid software. Raid Mode Switching Method Disconnect the power, use a screwdriver, toggle the paddle to the corresponding mode, press and hold the reset button, turn on the power, hold reset for ten seconds, the raid mode will be successfully switched.
- 【Up to 5Gbps】This raid enclosure equips with JMS567+JMB393 chip and USB 3.0, eSATA output interface.
Mirroring
Mirroring writes duplicate data to separate drives. If one member drive fails, the duplicate may keep the data available, but the copies consume capacity that could otherwise hold unique data.
Parity
Parity stores additional information across an array that can help reconstruct data after a supported number of drive failures. It adds overhead and affects writes; the number of failures the array can tolerate depends on the level and configuration.
Rank #2
- High Speed Data Transmission: The D2-320 hard drive enclosure (a DAS, NOT a NAS) adopts USB 3.2 Gen2 protocol for high-speed data transmission up to 10Gbps. With 2 hard drives in RAID 0, the read/write speed can reach up to 521MB/s (SATA III HDD 8TB x 2). With 2 SSD's in RAID 0, the read speed can reach 1075MB/s (SATA III 1TB SSD x 2)
- Multiple RAID Configurations: The D2-320 is a hardware RAID enclosure and it supports RAID 0, RAID 1, JBOD and SINGLE which can better satisfy various demands of users. In RAID 1, data will be in a mirror backup. When there is a damaged hard drive, you can directly replace the hard drive, and the data will be recovered automatically. This provides an absolute security for the data
- Super-Large Storage Capacity: The D2-320 USB storage enclosure can support up to two 3.5" and 2.5" SATA HDD, as well as 2.5" SATA SSD, with a maximum capacity of 22TB per drive, providing users with up to 44TB (22TB x 2) of storage space
- Intelligent Temperature Control: The D2-320 HDD enclosure has an intelligent temperature-controlled and low-noise fan that automatically adjusts its speed based on the temperature of the hard disk. This feature ensures that the hard disk operates at its best temperature and provides better heat dissipation
- Tool-Free Hard Drive Installation: The D2-320 external hard drive enclosure features a tool-free hard drive tray design that allows for easy installation and removal of hard drives without the need for any tools. Furthermore, the D2-320 incorporates a brand new Push-lock unique design from TerraMaster, which automatically locks the hard drive tray when you insert the hard drive, preventing the hard drive from falling out or disconnecting
What is the difference between RAID 0, RAID 1, RAID 5, RAID 6, and RAID 10?
| Level | Data arrangement | Drive-failure tolerance | Main trade-off |
|---|---|---|---|
| RAID 0 | Striping without redundancy | None; failure of a member drive can make the array unavailable | Uses capacity without mirroring or parity protection |
| RAID 1 | Mirroring | Duplicate data can remain available after a member failure, depending on the arrangement | Mirrored copies reduce usable capacity |
| RAID 5 | Striping with single distributed parity | Can reconstruct data after one member drive failure | Parity consumes capacity and creates write trade-offs |
| RAID 6 | Striping with dual distributed parity | Can support recovery after up to two drive failures in the documented arrangement | Additional parity has additional overhead |
| RAID 10 | Striping across mirrored pairs | Depends on which member drives fail and the implementation | Combines striping and mirroring, using capacity for duplicate data |
These are general descriptions, not a guarantee that a particular computer, controller, operating system, or storage product supports each level or behaves identically. Intel’s documentation describes levels supported by the controllers it covers; Intel’s RAID documentation is specific to that hardware context. Synology also outlines RAID types and storage trade-offs in its RAID overview.
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Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →How should you choose a RAID level?
There is no universally best RAID level. Compare the options against the actual drive arrangement and workload rather than treating a level number as a performance guarantee.
Rank #3
- 【Reliable External Storage System for Individuals and business】The 3.5 hard drive enclosure supports 2.5/3.5 inches HDD and SSD, max capacity up to 20TB for each hard drive, it's a ideal external hard drive enclosure for personal or enterprise using.Save space on your desktop or laptop.
- 【4 Raid Modes】!!!NOTE:Press and hold the "Reset" button for 5 seconds after reset the RAID array!!!This raid enclosure supports 4 RAID Modes(RAID 0, RAID 1, Normal, JBOD).Designing RAID may result in data loss.MAC OS no Raid software.
- 【No heat】The 2 bay hard drive reader built in Aluminum-Alloy materials and 2 inch Fan.Maximize the security of your data.NOTE：Fan noise is around 40-50 decibels, not recommended if you are very sensitive to noise.
- 【Up to 5Gbps】This dual bay raid enclosure equips with JMS561 chip and USB 3.0 output interface.
- 【Wide Compatibility, Plug and Play】Equipped with USB A/C 3.0 Cable.Compatible with Windows 7 and above, Mac 9.1 and above, Linux.Plug and play, no fuss, no muss.
- Failure tolerance: Identify how many drive failures the configuration can withstand and whether the specific failure pattern matters.
- Usable capacity: Account for capacity used by mirrors or parity, not just the total capacity printed on the installed drives.
- Workload: Read and write behavior varies by level, implementation, and workload. Parity writes may impose a meaningful cost.
- Drive count: Check the level’s minimum drive requirements and the limits of the controller or storage software.
- Expansion and rebuilds: Confirm whether the system supports adding capacity later and understand how it handles a failed drive and reconstruction.
Provider guidance can be specific to its service. For example, AWS does not recommend RAID 5 or RAID 6 for Amazon EBS because parity writes consume IOPS available to the volumes. That is guidance for EBS, not a universal rule for on-premises arrays; see AWS’s RAID configuration guidance.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What RAID does—and does not—tell you
The term RAID alone does not reveal how much capacity is usable, how the array performs, or how many drive failures it can tolerate. Those answers depend on the RAID level, the number and arrangement of drives, and the implementation. Check the documentation for the specific controller, operating system, or storage product before choosing or changing an array configuration.
Rank #4
- !!!NOTE:When the 8-bay enclosure being used, there is at least one hard drive must be inserted into HDD1-HDD4, same goes for HDD5-HDD8, 2 HDDs is a minimun quantity to be inserted.Please read the instructions carefully before trying!!!Be sure to save a good backup of your data before setting up RAID, which will format your hard drive after setting up RAID!!!!!!
- NOTE: When using this product, please first confirm that the hard drive loaded into this product is normal, otherwise it will lead to not out of the drive, such as loading more than one hard drive, it will only show one, can not confirm which one is bad, please load a hard drive, power on, out of the drive a, confirm that it is normal, turn off, and then load the second, in the power on, out of the drive two, to confirm that it is normal, and so on, one by one to load, until you find the The problematic hard drive. For example, if there is a problem with one of the 8 hard drives, only one drive will come out.
- 【Reliable External Storage System for Individuals】The 3.5 hard drive enclosure supports 2.5/3.5inches HDD and SSD , max capacity up to 160TB( 20TB for each hard drive), Not compatible with WD 20TB hard drives, but supports Seagate 20TB hard drives.it's a ideal external hard drive enclosure for personal or enterprise using.Save space on your desktop or laptop.
- 【8 Raid Modes】This external raid enclosure supports CLONE, LARGE/ LARGE*2, NORMAL, RAID0*2, RAID5*2, RAID50, RAID00. NOTE:When replacing RAID, you need to go back to NORMAL/PM10 and set the desired RAID mode.Designing RAID may result in data loss. !!!Raid Mode Switching Method!!! Disconnect the power, use a screwdriver, toggle the paddle to the corresponding mode, press and hold the reset button, turn on the power, hold reset for ten seconds, the raid mode will be successfully switched.
- 【No heat】The 8 bay hard drive reader built in Aluminum-Alloy materials and two 2.9 inch Fans.Maximize the security of your data. NOTE：Fan noise is around 40-50 decibels, not recommended if you are very sensitive to noise.
RAID’s underlying ideas have a longer technical history: the foundational paper by Patterson, Gibson, and Katz introduced the concept in 1988. The paper is historical background rather than a source for present-day product capabilities: A Case for Redundant Arrays of Inexpensive Disks (RAID).
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Quick Recap
Best Value
- [Flexible RAID Mode Management]: This 3.5-inch RAID HDD enclosure supports eight configuration modes, namely 0, 1, 3, 5, 10, JBOD, CLONE, and CLEAR. It enables dual data backup, enhances data security, and caters to the individualized needs of diverse users. Note: It is advisable to back up your data before mode switching. If you have any inquiries, please do not hesitate to contact us
- [Supports 22TB Single Disk]: The 5-bay HDD enclosure accommodates 3.5-inch SATA disks, and the maximum storage capacity amounts to 110TB. It can effortlessly fulfill the storage requirements of large-scale engineering projects, high-resolution video footages, and other large-capacity data, eliminating concerns about capacity shortages
- [5Gbps Data Transfer]: The USB 3.0 interface of the external hard drive bay is compatible with SATA 6 Gbps, and the transfer speed reaches up to 235MB/s, facilitating effortless backup and transfer of files and videos, enabling centralized management and enhancing work efficiency
- [Effective Heat-dissipation]The 3.5-inch aluminum HDD case is outfitted with an 80mm silent cooling fan. Front and rear vents are designed, and the airflow effectively dissipates heat, ensuring the stable and efficient operation of the equipment over an extended period
- [Safety Protection]: The RAID enclosure features a bracket-free design for quick disassembly and assembly and possesses an independent safety locking mechanism to effectively prevent the unexpected removal or loss of the hard disk and guarantee the security of data
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