Drobo Mini
The world's smallest, most advanced storage array

BeyondRAID:

What's BeyondRAID? Storage without limitations.

BeyondRAID technology, built into every Drobo, delivers all of the benefits of traditional RAID, while providing much more and leaving many of the limitations behind. This next-generation of redundant storage technology brings together enhanced protection, reliability, expandability, and ease-of-use.

Drobos, based on BeyondRAID, interact with computing systems in the same manner as storage arrays using traditional RAID, so installing a Drobo allows you to maintain your current operating system and file system. This eliminates the challenges and costs when moving to a new storage technology.

Problems with Traditional RAID

Developed in the 1980s, RAID (Redundant Array of Inexpensive Disks) was designed to pool disk drives together for increased capacity and reliability for data storage. It has been preventing single disk drive failures causing data loss, and has been used in almost every enterprise data center for decades.

While reliable, the complexity of RAID is a huge challenge for small businesses and consumers. RAID has a high learning curve with many options, levels, and unfamiliar terminology like striping, mirroring, and parity.

There are several primary challenges with traditional RAID:

• Lock-in of RAID Levels
  To change RAID levels, most storage arrays require the data to be moved off, reconfigured, and then moved back on. If you want to move to RAID 6 from RAID 5 for protection against two drive failures, you need to reinitialize and start over. This process could take days to complete.
• Lack of Expandability
  Once drives are configured into a RAID pool, expandability is impossible unless you have a lot of time, or experience. If you want to add more storage capacity, the solution is to create a new RAID pool, leaving you with another chunk of storage to manage – or you can just reinitialize and start over.
• Drive Failures Create Big Risks
  When a drive fails, most RAID implementations enter a state where data loss will occur if another drive falters before the user replaces the failed drive. Also, performance is hampered when in this debilitated state.

Moving Beyond RAID

Drobo’s BeyondRAID technology solves the fundamental issues that traditional RAID can’t. Built on the foundation of traditional RAID, BeyondRAID adds a layer of virtualization that chooses the correct protection algorithm based on data availability needs at any given moment. Since the technology works at the block level, it can write blocks of data that alternate between RAID protection levels.

If you need to add storage capacity to a Drobo, simply insert additional disk drives or replace the smallest disks with larger ones – no need to change RAID levels, purchase a new storage array, or go through the complex administration of pooling RAID groups.

The BeyondRAID feature can even switch from single to dual disk redundancy with just the click of your mouse through Drobo Dashboard. This ensures enterprise-level dual parity data protection, when needed. If a drive happens to fail, Drobo will automatically re-layout the data to the remaining drives, returning it to a protected state with no user interaction.

Available Features	RAID 1	RAID 5	RAID 6	Everyone Else with RAID	BeyondRAID
Supports Two Drives
Supports Three Drives
Support Four Drives or More
Single Disk Redundancy
Dual Disk Redundancy					1
Mixed Drive Utilization
Thin Provisioning				*
Instant Expansion
Smart Volumes					2
Mixed Drive Utilization
Automatic Protection Levels
Virtual Hot Spare
Data Aware
Drive Re-ordering

* Some vendors (e.g. Synology) offer some options, though they require manual choices / configuration.
¹ Available with 5-bay or Larger Drobos
² Available with iSCSI-capable Drobos

Thin Provisioning is a fundamental capability of BeyondRAID, allowing for infinite capacity expansion by just replacing a drive with a larger one.

Instant Expansion occurs when a new, or larger, drive is inserted without any disruption in service.

Drobo's volumes are Smart Volumes, pulling needed storage from a common pool and then returning deleted blocks back to the common pool, preventing free space from being tied up by any particular server.

Mixed Drive Utilization allows you to insert any drive, of any size, or any type, and Drobo will optimally use it - check out our interactive Capacity Calculator.

Automatic Protection Levels ensures the best algorithm is used to protect from drive failure depending on the number of drives that are inserted, without any user configuration. There is no need to learn about RAID levels or what mirroring or striping is.

Dual Disk Redundancy enhances BeyondRAID protection by guarding from multiple drive failures in a short period of time. Even if two drives fail, BeyondRAID will attempt to use the remaining drives to return to a protected state.

Virtual Hot Spare utilizes all drives at all time with no drives sitting idle waiting for one to fail. With some traditional RAID systems, a drive can be marked as a "hot spare", waiting on standby for a drive failure so it can take over. That's just a unutilized drive that you have to pay for taking up a valuable drive bay.

Drobos are Data Aware, intelligently handling data for added resiliency, performance, and management. Being Data Aware allows the Drobo to have a capacity gauge on the front, quickly recover in the event of a drive failure, enable intelligent tiering of data, and much more.

Drive Re-ordering allows Drobo disk packs to be moved to another Drobo, and even re-ordered, while still functioning - try that with RAID.

How BeyondRAID Works

Now that we've looked at how BeyondRAID compares with traditional RAID and the value that it brings, let's see how BeyondRAID works.

The sections of the RAID stack are drastically reinvented in a Drobo—and it all has to
do with how drives are pooled (disk pack) and the way data is stored (BeyondRAID virtualization).

Thin Provisioning with Smart Volumes

Our volumes are just smarter. Thin provisioning through Drobo's Smart Volumes provides on-demand allocation of storage providing maximized capacity utilization. Smart Volumes are a virtual volume architecture that pull needed storage, on-demand, from a common pool (thin provisioning) and then return any deleted blocks back to the common pool (thin reclamation), allocating these newly available blocks to free space immediately available for new data.

Space allocation is automatically managed, maximizing storage resources. For example, if a large file on a volume is deleted, the free space of the Drobo gets larger. The freed up space is then available to other volumes. Our Volumes are Smart, even enterprise-class arrays with thin provisioning do not return consumed storage back to a common pool at this granular level.

Thunderbolt Technology:

The Fastest Connection To Your PC Experience

With Drobo Thunderbolt connectivity, data to and from the device will run up to 20 times faster than with USB 2.0 connectivity and up to 12 times faster than with FireWire 800. In addition to Thunderbolt, Drobo will make significant increases in processing power and add support for solid state drives (SSDs) to ensure top performance. Further enhancements to form factor, power management, and cooling technology result in an overall design that is not only significantly faster, but also more compact, greener, and quieter than ever before.

What is Thunderbolt technology?

Thunderbolt technology is the fastest way to transfer data between a PC and peripheral and display devices. Thunderbolt I/O technology lets you move data between your devices and your computer with 2 channels of 10Gbps flowing both ways (upstream and downstream) at the same time. And it allows you to connect as many as 6 devices, daisy chained, through a single compact port.

Thunderbolt technology is a foundation for innovative new product development that can expand PC capabilities and performance, quickly and easily, enabling a whole new market for innovative devices.

At 10 Gbps, Thunderbolt™ technology enables products that can

• Transfer a full-length HD movie in less than 30 seconds
• Backup 1 year of continuous MP3 playback in just over 10 minutes

Another industry first

Developed by Intel, and brought to market with technical collaboration from Apple. Thunderbolt™ technology is a new, high-speed I/O technology designed for performance, simplicity, and flexibility.

How Thunderbolt technology works

Intel Thunderbolt™ controller chips interconnect a PC and other devices, transmitting and receiving information for both PCI Express (PCIe) and DisplayPort protocols. The Thunderbolt™ controller chip switches between the two protocols to support communications over a single cable. Intel is making its controller chips available to the industry, and is working with other component manufacturers to deliver the Thunderbolt™ connectors and cables.

The Transformational PC I/O

Thunderbolt™ technology is a transformational I/O innovation that provides a leap in performance over current I/O technologies with 10 Gbps of full-duplex bandwidth per channel. It significantly simplifies the end-user experience by concurrently supporting data (PCI Express*) and display (DisplayPort) connections over a single cable. Thunderbolt products may be connected using electrical or optical cables. Thunderbolt technology enables flexible and innovative system designs by allowing multiple, high-performance, PCI Express and DisplayPort devices to attach to a computer through a single physical connector

Why Thunderbolt Technology Matters

Data transfers for backup, sharing, and editing are faster with Thunderbolt technology, significantly reducing times to complete these tasks.For time-sensitive data, such as video and audio during creation and playback, data transfers can be critical to the success of the work. Thunderbolt technology was specifically designed with video and audio applications in mind with inherently low latency and highly accurate time synchronization capabilities.

For some power users, optimal workflows can be had with workstation performance and expandability while using a thin and light laptop. Thunderbolt technology enables using the thinnest and lightest laptops, connected, with “in the box” performance over a single external cable, to high-performance external media drives, HD displays, HD media capture and editing systems, as well as legacy I/O hubs and devices, for the utmost in performance, simplicity and flexibility.

Rethinking I/O

As every generation of information technology progresses, I/O technologies evolve to provide higher bandwidth for getting data into and out of computers. At its simplest, two discrete types of I/O have resulted – display (with formatted video and audio components), and data.

Traditional approaches to this evolution have been to make an existing technology faster. Thunderbolt technology combines the next step in higher performance with the innovation of mapping two of the most fundamental I/O protocols at the heart of computing (PCI Express and DisplayPort), onto a single highly efficient meta-protocol, transmitting them over a single cable, and managing the traffic routing (supporting daisy chaining and hot-plugging devices) with intelligent hardware controllers.

The choice of PCI Express was clear, providing for off-the-shelf controller use to attach to nearly any technology imaginable, and the choice of DisplayPort was equally clear for meeting the needs of the PC industry with capabilities like support for greater-than-high- definition display resolutions, and support for up to 8 channels of high-definition audio.

Protocol Architecture

Thunderbolt technology is based on a switched fabric architecture with full-duplex links. Unlike bus-based I/O architectures, each Thunderbolt port on a computer is capable of providing the full bandwidth of the link in both directions with no sharing of band- width between ports or between upstream and downstream directions. The Thunderbolt protocol architecture can be abstracted into four layers.

A Thunderbolt connector is capable of providing two full-duplex channels. Each channel provides bi-directional 10 Gbps of band- width. A Thunderbolt connector on a computer is capable of connecting with a cable to Thunderbolt products or to DisplayPort devices. The Thunderbolt connector is extremely small, making it ideal for thin systems and compact cables. Compatibility with DisplayPort devices is provided by an interoperability mode between host devices and DisplayPort products; if a DisplayPort device is detected, a Thunderbolt controller will drive compatibility mode DisplayPort signals to that device. Thunderbolt cables may be electrical or optical; both use the same Thunderbolt connector. An active electrical-only cable provides for connections of up to 3 meters in length, and provides for up to 10W of power deliverable to a bus-powered device. And an active optical cable provides for much greater lengths; tens of meters.

The Thunderbolt protocol physical layer is responsible for link maintenance including hot-plug detection, and data encoding to provide highly efficient data transfer. The physical layer has been designed to introduce very minimal overhead and provides full 10Gbps of usable bandwidth to the upper layers.

The heart of the Thunderbolt protocol architecture is the transport layer. Some of the key innovations introduced by the transport layer include:

• A high-performance, low-power, switching architecture.
• A highly efficient, low-overhead packet format with flexible QoS support that allows multiplexing of bursty PCI Express transactions with isochronous DisplayPort communication on the same link.
• A symmetric architecture that supports flexible topologies (star, tree, daisy chaining, etc.) and enables peer-to-peer communication (via software) between devices.
• A novel time synchronization protocol that allows all the Thunderbolt products connected in a domain to synchronize their time within 8ns of each other. DisplayPort and PCI Express protocols are mapped onto the transport layer. The mapping function is provided by a protocol adapter which is responsible for efficient encapsulation of the mapped protocol information into transport layer packets. Mapped protocol packets between a source device and a desti- nation device may be routed over a path that may cross multiple Thunderbolt controllers. At the destination device, a protocol adapter recreates the mapped protocol in a way that is indistinguishable from what was received by the source device.

The advantage of doing protocol mapping in this way is that Thunderbolt technology-enabled product devices appear as PCI Express or DisplayPort devices to the operating system of the host PC, thereby enabling the use of standard drivers that are available in many operating systems today.

Controller Architecture

A Thunderbolt controller is the building block used to create Thunderbolt products. A Thunderbolt controller contains:

• A high-performance, cross-bar Thunderbolt protocol switch
• One or more Thunderbolt ports
• One or more DisplayPort protocol adapter ports
• A PCI Express switch with one or more PCI Express protocol adapter ports

The external interfaces of a Thunderbolt controller that are connected in a system depend on the application for which the system is designed. An example implementation of a host-side Thunderbolt controller is shown in Figure 4. Host- side Thunderbolt controllers have one or more DisplayPort input interfaces, a PCI Express interface along with one or more Thunderbolt technology interface. By integrating all the features necessary to implement Thunderbolt into a single chip, the host-side controller enables system vendors to easily incorporate Thunderbolt technology into their designs.

Thunderbolt technology leverages the native PCI Express and DisplayPort device drivers available in many operating systems today. This native software support means no extra software development is required to use a Thunderbolt technology-enabled product

Thunderbolt Technology Possibilities

With Thunderbolt products, performance, simplicity and flexibility all come together. Users can add high-performance features to their PC over a cable, daisy chaining one after another, up to a total of 7 devices, 1 or 2 of which can be high-resolution DisplayPort v1.1a displays (depending on the controller configuration in the host PC). Because Thunderbolt technology delivers two full-bandwidth channels, the user can realize high bandwidth on not only the first device attached, but on downstream devices as well.

Users can always connect to their other non-Thunderbolt products at the end of a daisy chain by using Thunderbolt technology adapters (e.g., to connect to native PCI Express devices like eSata, Firewire). These adapters can be easily built using a Thunderbolt controller with off-the-shelf PCI Express-to-“other technology” controllers

System designers taking advantage of Thunderbolt technology can pursue ever thinner and lighter system designs, using fewer connectors while still achieving high performance between their products and external devices. With Thunderbolt technology, workstation-level performance feature expansion can be packaged as standalone accessories, and is only a cable away. And by leveraging the inherently tight timing synchronization (within 8ns across 7 hops downstream from a host) and low latencies of Thunderbolt technology, broadcast-quality media can be produced using Thunderbolt products.

Data-Aware Tiering:

How do small and medium business (SMB) IT administrators effectively use solid state drives (SSDs) to accelerate their applications? They can't. Either the array is too expensive or the drives must be in their own pool and separate from the rest of the data. Data must be sent manually to the fast volume (SSD) or to the normal volume.

How can the IT administrator figure out what data is transactional in nature, that is, what data should be sent to the fast volume? To make things even more confusing and complicated, data can have mixed characteristics. But to get the most out of expensive SSDs, the solution must be intelligent and fully automatic—the data just needs to go to the right place automatically.

A Drobo is a single pool of drives by design. The user does not need to think about pooling drives or creating RAID groups. Also, drives of different sizes and types can be used in a Drobo. These advanced technologies make Drobos ideal for allowing SSDs and hard disk drives (HDDs) to work together optimally in the same chassis – automatically!

To enable use of drives of different sizes, the Drobo virtualization layer (see BeyondRAID section) sits on top of the physical drives. Because Drobos are data aware, data is placed intelligently in the best place on the drives. With the introduction of SSD support in the Drobo B1200i, Drobo 5D, and Drobo Mini, SSDs provide a faster tier of storage for data that is transactional in nature, the type of data that benefits from the faster write and access speeds SSDs provide.

Tiering is for Professionals

While automated data tiering helps IT administrators accelerate business critical applications, it is also ideal for accelerating the applications you need to run faster on YOUR computer too. If you ever wished that database-driven applications such as Aperture, Lightroom, or iTunes were a bit snappier, Drobo is here to help.

Since just a little bit of high-speed flash goes a long way to accelerate your storage, we added an additional drive bay to the Drobo 5D and Drobo Mini. It’s called the Drobo Accelerator Bay and it accepts an industry-standard mSATA SSD. Since these very compact SSDs are being used in the new Ultrabook family of portable computers, they are becoming readily available and very affordable. So you can add flash to your Drobo without consuming one of the standard drive bays, which are best used to maximize capacity.

Tiering on Smaller Drobos

On the larger Drobo B1200i, there are enough drive bays to create two tiers of storage while still maintaining high capacity. On 4- and 5-bay Drobo devices, there are not enough bays to create two tiers of storage, so we had to implement tiering differently.

The mSATA SSD is used to accelerate smaller and random reads from the Drobo, while the HDDs are used for storing and streaming larger data such as photos, video, and user documents.

Note: that Data-Aware Tiering is currently available only for the Drobo B1200i, Drobo 5D, and Drobo Mini.

SSD Support

With the introduction of SSD support in the Drobo B1200i, SSDs provide a faster tier of storage for data that is transactional in nature, the type of data that benefits from the faster write and access speeds SSDs provide. As data enters the Drobo, if it is transactional, then the data is written to the "transactional" tier comprised of SSDs. If the data is a sequential stream, it is written to the “bulk tier” comprised of hard disk drives (HDDs). Unlike enterprise arrays with auto-tiering, transactional data goes directly to SSDs, which ensures that BOTH writes AND reads are optimized.

Being Data Aware

As data enters the Drobo, if it is transactional, then the data is written to the faster tier of SSDs. Unlike enterprise arrays with auto-tiering, transactional data goes directly to SSDs, which ensures that BOTH writes AND reads are optimized.

As data is being written to the Drobo, transactional data (shown in red) is written
to the faster tier and other data is written to the bulk tier.

Drobo's tiering functionality allows you to store any type of data on the Drobo and the data that can be optimized by SSDs is automatically optimized in flight. This means that all data—mixed data types from 10 or more VMs in a vSphere cluster, Exchange databases/datastores, backup data, or files on a file server—automatically goes to the right place.

One Pool, Multiple Tiers

As detailed in the BeyondRAID section, a Drobo is a single pool of drives. Whether you put three drives or 12 drives in a Drobo, they are all part of the same disk pack.

Two tiers of storage automatically configured in the same Drobo disk pack.

Whether you have 8 HDDs and 2 SSDs or 9 HDDs and 3 SSDs, they will be utilized appropriately without any upfront setup. All the administrator has to do is put the drives in the Drobo.

Fully Automated Tuning

After data is written to storage, data patterns often change. Sometimes a large amount of data is written to storage and not read for weeks or even months. On the other hand, it is not uncommon for a small amount of data to be written and accessed very frequently.

With Drobo's automated tiering, optimization of data doesn't stop when the data reaches a transactional or bulk storage tier. As the stored data is being read off the Drobo, the data is patterned and optimized in the background. Data that becomes hot will be moved to the transactional tier and visa versa. If data on the bulk tier is frequently read and begins to look more like transactional data, it will be migrated to the transactional tier. If data on the transactional tier becomes "cold" with very few or no read requests, it will be migrated to the bulk tier. These migrations occur in the background when the storage is not under high load and do not require any administrative interaction.

When data becomes "cold" it is migrated to the bulk tier.
When data becomes "hot" it is migrated to the transactional tier.

Tiering Without SSDs

Even when a Drobo doesn't contain SSDs, Drobo still puts its automatic tiering feature to work. Without SSDs, the advantage of tiering is to eliminate the write penalty when parity data is created.

As discussed in the BeyondRAID section, a Drobo can automatically have zones of different types. Even when all HDDs in the Drobo are the same, Drobo lays out zones differently on the transactional tier than it does on the bulk tier.

Drobo creates different zone types on transactional and bulk tiers
to tune the storage appropriately for hot and cold data.

For example, mirror zones are more optimized for writes and stripes are more optimized for capacity. Leveraging BeyondRAID technology, zones are automatically created and altered on the fly to optimize the Drobo for the type of data you store on it.

Just Add SSDs … Really!

If your Drobo contains only HDDs, but if your applications need even more performance, all you have to do is introduce SSDs to the Drobo. The SSDs then become the transactional tier and all of the HDDs are delegated to the bulk tier. The only administrative task is to insert new drives into the Drobo.

Technology:

BeyondRAID Technology
Most modern storage arrays aggregate disks and prevent against single drive failures using a 20-year-old technology called RAID (Redundant Array of Independent Disks). While RAID has served many businesses well, it requires up-front knowledge of its functionality and has many shortcomings. BeyondRAID technology built into every Drobo addresses these shortcomings and makes virtualizing disk drives usable by everyone. BeyondRAID provides these enhancements over traditional RAID:

• Thin Provisioning as a fundamental capability allows for infinite capacity expansion by just replacing a drive with a larger one
• Instant Expansion occurs when a new, or larger, drive is inserted without any disruption in service
• Mixed Drive Utilization allows you to insert any drive, of any size, or any type, and Drobo will optimally use it - check out our interactive Capacity Calculator
• Automatic Protection Levels ensures the best algorithm is used to protect from drive failure depending on the number of drives that are inserted without any user configuration
• Dual Disk Redundancy enhances BeyondRAID protection by guarding from multiple drive failures
• Virtual Hot Spare utilizes all drives at all time - no drives sitting idle waiting for one to fail
• Drobos are Data Aware, intelligently handling data for added resiliency, performance, and management
• Drive Re-ordering allows Drobo disk packs to be moved to another Drobo, and even re-ordered, while still functioning - try that with RAID

Drobo Dashboard Management
Drobo Dashboard is the single tool to centrally manage all of your Drobos. Drobo Dashboard gives you status as if all of your Drobos were right in front of you by providing you the same status lights and capacity guage that are on the front panel. All adminitration tasks are a single click away and there's even a built-in data protection tool called Drobo Copy to easily copy data to and from your Drobo. Simply, it's the easiest way to configure and manage business-class storage.

Learn more about Drobo Dashboard.

Thunderbolt Technology
Drobo Thunderbolt connectivity, data to and from the device, will run up to 20 times faster than with USB 2.0 connectivity and up to 12 times faster than with FireWire 800. In addition to Thunderbolt, Drobo will make significant increases in processing power and add support for solid state drives (SSDs) to ensure top performance. Further enhancements to form factor, power management, and cooling technology result in an overall design that is not only significantly faster, but also more compact, greener, and quieter than ever before.

Data-Aware Tiering
Data-Aware Tiering SANs allow businesses to consolidate storage resources and share that storage across all connected servers and their applications. The reality is that different applications have different workloads. Transactional databases require different storage behavior than streaming media applications. Traditional storage has treated all workloads as equal, not optimizing for any of them.

It's called the Drobo Accelerator Bay and it accepts an industry-standard mSATA SSD. So you can add flash to your Drobo without consuming one of the standard drive bays, which are best used to maximize capacity. The mSATA SSD is used to accelerate smaller and random reads from the Drobo, while the HDDs are used for storing and streaming larger data such as photos, video, and user documents.

File and Operating System Agnostic
Drobo and its underlying BeyondRAID technology currently support the Windows and Mac platforms, with file system support for NTFS, HFS+ and FAT32. Since Drobo is a block level system, it easily adapts to almost any environment.

Mixed Drive Capacity Utilization
Grow storage to meet your data capacity needs with minimal effort. To add capacity, simply insert a new hard disk or replace the smallest disk with a larger one, even when all four disk bays are full. Unlike traditional RAID systems, the BeyondRAID technology enables IT managers to efficiently mix and match disk brands, capacities, and speeds. This allows for continuous expansion as disk capacities grow. Now, expansion is automatic, instantaneous and access to data is always maintained.

To find out exactly how much free capacity you'll have with your choice of disk capacities, try out our interactive Capacity Calculator on tab.

Redundant Safety
Drobo can ensure your data is safe even if a hard disk fails. You'll feel safer knowing that if disks do fail, Drobo automatically enters a state of self-healing wherein it relays out your data across the remaining healthy disks and sectors.

Proportional Rebuild Times
The time it takes Drobo to rebuild data after a drive failure or removal is proportional to the amount of data stored in the pool — meaning the less capacity that is used, even on a 2TB disk, the shorter your rebuild times will be. This is superior to traditional RAID, which lacks proportional rebuild times, and is forced relay out every drive block even if it does not contain user data.

Since Drobo is "Data Aware", it tracks where data is on each disk, so it can differentiate between used and unused portions of disk. This expedites rebuild times and reduces your risk of losing data to an additional disk failure. In short, your data is safer on a Drobo.

Self-Healing
When Drobo detects a "bad" hard disk, it proactively advises you with a series of warnings ranging from a blinking red LED on its front panel, to pop-up alerts in Drobo Dashboard, to email alerts. What Drobo does next is exceptional. It enters a self-healing mode where it repairs around the bad sector or disk, and will work until it returns to the safest state possible. If Drobo has sufficient time and free capacity (indicated by all lights returning to a solid green state), it can even withstand additional hard disk failures — that's the power of self-healing.

Storage Virtualization
BeyondRAID was designed from the ground up to allow the storage capacity of the array to expand and contract. BeyondRAID makes this a simple process by utilizing a technology called "virtualization." Virtualization provides a layer of abstraction between the data requested by the file system and the physical location of that data on the disk drives. A given piece of data can be located on any drive, and on any physical location on that drive. This is what makes adding a drive to a Drobo so simple. The new drive just provides additional places to store data.

Virtualization is what enables BeyondRAID to effortlessly change the data arrangement on the drives, for example, changing data stored as a mirror into data stored as parity stripe, without interrupting the user access to data. Virtualization completely decouples the physical space available in the array from the space reported to the operating system. This is how BeyondRAID is able to eliminate the need to manually expand/contract the file system as more space becomes available or is removed.

Thin Provisioning
Thin provisioning is a technical term that describes how the BeyondRAID technology communicates with your operating system. BeyondRAID communicates with your OS about how much disk space you have, up to 16TB (this varies with older operating and file systems). Specifying a larger amount of storage than is physically available allows you to grow into the volume without having to reformat or migrate your data in order to add capacity. BeyondRAID automatically also reclaims space as you delete files.

Self-Managing
Drobo is highly automated storage. There are no complex configuration screens, DIP switches, confounding choices, web consoles or other complications that prevent so many other storage devices from working out of the box.

Drive Reordering
One long-standing requirement inherent in traditional RAID-based systems was that if for some reason you needed to remove the drives, you'd have to replace the drives in the exact same order. When you remove your disks from Drobo, you can put them back in any order you like.

Specifications:

Drobo Mini Technical Specifications
Capacity	Up to four (4) 2.5" SATA I/II/III hard disk drives or solid state drives – 7 mm and 9.5 mm in height (sold separately). One (1) mSATA solid state drive in the Drobo Accelerator Bay for increased performance (sold separately). Drives of any manufacturer, capacity, spindle speed, and/or cache can be used. No carriers or tools required. Expandable by adding drives or hot-swapping drives with larger ones. Use the Capacity Calculator to estimate available storage in various configurations.
Connectivity	2 x Thunderbolt ports; second port for daisy chaining Thunderbolt devices (Mac OS X only) 1 x USB 3.0 port
File System Options	Windows: NTFS Mac OS X: HFS+
BeyondRAID Features	Thin Provisioning Instant Expansion Mixed Drive Size Utilization Automatic Protection Levels Dual Disk Redundancy Virtual Hot Spare Data Aware Drive Re-ordering
Additional Software Features	Hot Data Caching Drive Spin Down Dim Lights OS X Time Machine Support
Hardware Features	Carrier-less Drive Bays Power Fail Protection Kensington Lock Port for Security (lock not included)
Operating System Support	Mac OS X 10.7 and higher Windows 8/8.1 32 and 64 bit Windows 7 32 and 64 bit
Management	Drive bay indicator lights, capacity gauge, status lights Drobo Dashboard version 2.3 or later
Dimensions	Width: 7.3 in (187.2 mm) Height: 1.8 in (44.6 mm) Depth: 7.1 in (180.0 mm) Desktop Form Factor
Weight	2.2 lb (without hard drives, power supply, or packaging)
Power and Cooling	External Power Supply: AC Input – 100-240VAC~2A, 50-60Hz DC Output – 12V, 4.16A, 50W max Dual, fixed, variable speed cooling fans
Box Contents	Drobo Mini 3.3 ft (1 m) USB 3.0 cable 7.5 ft (2.2 m) power cord with power supply Quick Start Card
Optional Accessories	Drobo Mini Carrying Case

Diagram:

Sample Light Indicators Diagram

Video:

Documentation:

Download the Drobo Mini Datasheet (.PDF)