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Simple, scalable, reliable Drobo Storage ProductsWhich Drive Is Right for Your Drobo?


Drobo gives you the flexibility to use a wide variety of drive types and capacities, but with many drive options to choose from, the process of getting the ideal drive is challenging. Not all drives are the same and if you do not choose the right one, your Drobo's performance may not meet your expectations.

Find the information you need right here!

Drive Options:

Drives TypesHere are options you should consider when evaluating drives:

  1. Type – Multiple Drobo models now support hard disk drives (HDDs) and solid state drives (SSDs). HDDs provide high capacity while SSDs provide high performance. When SSDs are supported, they can be used alongside HDDs, so you can have both capacity AND performance.

  2. Grade – Quality is important when deciding what drive to use. If you will be actively using the drives most of the day in a business environment, for example, you should use enterprise-grade drives. Enterprise drives have higher MTBF (Mean Time Between Failures), which is a good thing when used with applications in continuous use.

  3. RPM – When it comes to disk drive performance, the speed at which the disks spin is very important. Choose faster spinning drives (≥ 7200 RPM) for applications that can take advantage of higher-performance storage. For example, so-called "Green" (≤ 5600 RPM) drives have the lowest RPM rating and will be the slowest performing drives in a Drobo. For optimal performance, it's best not to mix 7200 RPM drives with slower drives. Also, it is not recommended to mix significantly different RPM speeds, such as 7200 RPM with 15,000 RPM in a Drobo B1200i.

  4. Capacity – With Drobo, you can choose the capacity that you need today and expand with larger capacity drives in the future. Remember, with drive redundancy in arrays such as Drobo, one or more drives is used to store parity data. Use the Drobo Capacity Calculator for specific information.

  5. Form Factor – All 3.5" drives are compatible with all Drobo models except the Drobo Mini. The Drobo Mini accepts 2.5" drives that are between 7 mm and 9.5 mm in height. Drobo's carrier-less design, requires no tools or screws to install.

  6. Cache – Most modern drives have a good amount of internal cache (32 or 64 MB), so this is not a critical deciding factor.

  7. Interface – All Drobos use SATA (SATA II/III) drives, but the Drobo B1200i can also use SAS drives. The main difference is that SAS drives are dual-ported, enabling a high-availability architecture such as can be found in the B1200i.

  8. Number of Drives – In all storage arrays, the more drives installed, the faster the performance. For example, if you are using a B800i in a VMware vSphere cluster, consider using 8 enterprise-grade drives instead of a smaller number such as 4. The same goes for the B1200i, where 12 drives are better for IOPS than 6. When using SSDs in a B1200i, most optimal drive configuration for virtual server primary storage is 9 SAS drives and 3 SSDs (dual disk redundancy enabled). A minimum of 6 hard drives is recommended with 3 SSDs.

  9. Price – Despite the many other things to consider, often the #1 deciding factor when people purchase drives is price. Since performance, reliability, and energy efficiency are also key purchase criteria, price should not be the only consideration. Purchasing high-quality drives will give you a better storage experience by reducing the chance of having to replace or rebuild a drive—ultimately saving you money.

Supported Drive Types:


  Drobo Drobo Mini Drobo 5D Drobo 5N Drobo B800FS Drobo B800i Drobo B1200i
"Green" SATA Disk Drives Green - Supported and Recommended Yellow - Supported Yellow - Supported Yellow - Supported Red - Not Supported Red - Not Supported Red - Not Supported
"Red" SATA Disk Drives Green - Supported and Recommended Red - Not Supported Green - Supported and Recommended Green - Supported and Recommended Red - Not Supported Red - Not Supported Red - Not Supported
7200RPM Performance SATA Disk Drives Green - Supported and Recommended Green - Supported and Recommended Green - Supported and Recommended Green - Supported and Recommended Red - Not Supported Red - Not Supported Red - Not Supported
Enterprise SATA Disk Drives Green - Supported and Recommended Red - Not Supported Green - Supported and Recommended Green - Supported and Recommended Green - Supported and Recommended Green - Supported and Recommended Yellow - Supported
Enterprise SAS Disk Drives Red - Not Supported Red - Not Supported Red - Not Supported Red - Not Supported Red - Not Supported Red - Not Supported Supported and Recommended
Solid State Drives (SSDs) Red - Not Supported Supported and Recommended Supported and Recommended Supported and Recommended Red - Not Supported Red - Not Supported Red - Not Supported
mSATA Solid State Drives (SSDs) Red - Not Supported Supported and Recommended Supported and Recommended Supported and Recommended Red - Not Supported Red - Not Supported Red - Not Supported
Enterprise Solid State Drives (SSDs) Red - Not Supported Red - Not Supported Red - Not Supported Red - Not Supported Red - Not Supported Red - Not Supported Supported and Recommended
Green - Supported and Recommended = Supported and Recommended: best drive type to use with this Drobo
Yellow - Supported = Supported: can be used with this Drobo, but not optimal
Red - Not Supported = Not Supported: do not use with this Drobo

Below are descriptions of supported drive types.

"Green" SATA Disk Drives - Available Here!

  • Home or home office environments where reduced noise and energy efficiency are more important than performance
  • Often the lowest-cost drive type
  • Examples are WD Caviar Green and Seagate Barracuda Green

"Red" SATA Disk Drives - Available Here!

  • Western Digital offers a drive designed for 2 to 5 bay desktop RAID arrays
  • Designed and tested for compatibility in 24x7 operating environments
  • Unique to Western Digital

Performance SATA Disk Drives - Available Here!

  • Home, professional, or small office environments where high-performance storage is required (≥ 7200 RPM)
  • Often more reliable and recommended above "green" drives
  • Examples are the WD Caviar Black and Seagate Barracuda XT

Enterprise SATA Disk Drives - Available Here!

  • Small and medium-sized business environments that require reliable and high-capacity storage that is affordable
  • Good for entry-level server virtualization, business applications, and backup
  • Examples are WD RE4 and Seagate Constellation ES.2 (SATA)

Enterprise SAS Disk Drives - Available Here!

  • Small and medium-sized business environments that require reliable, high-performance storage
  • Good for server virtualization and business applications
  • Dual-ported for a high-availability architecture. The Drobo B1200i comes with 7200 RPM SAS drives, which are optimized for high capacity. While the B1200i supports 15,000 RPM SAS drives, it is not recommended that you mix these two drive rotational speeds.
  • Examples are Seagate Constellation ES.2 (SAS) and HGST Ultrastar (SAS)

Solid State Drives (SSDs) - Available Here!

  • Professional or small office where maximum performance is required
  • Overall storage capacity is less compared to HDDs
  • Examples are OCZ Octane and Intel SSD 320

mSATA Solid State Drives (SSDs)

  • Professional or small office where maximum performance is required
  • Can be used in the Drobo Accelerator Bay, leaving the primary drive bays available for high-capacity HDDs
  • Consult the compatibility list for supported mSATA SSDs to use in Drobo 5D and Drobo Mini
  • Any capacity mSATA device can work; Drobo recommends 60-64GB as the optimal size

Enterprise Performance SAS Solid State Drives (SSDs)

  • Small and medium-sized business environments that require accelerated storage performance
  • Good for high-density server virtualization and business-critical applications such as Microsoft Exchange
  • Ideal when paired with Enterprise Performance SAS Disk Drives to create a multi-tier storage solution
  • Examples are OCZ Talos (Drobo-specific version) and Seagate Pulsar.2.

Solid State Drives (SSDs) for the Drobo B1200i:

Similar to HDDs, there is a big difference between consumer and enterprise grade SSDs. Consider the following when selecting SSDs for your Drobo B1200i:

  • SLC vs. MLC. Enterprise-grade SSDs used to be made exclusively of expensive SLC (single-level cell) flash, but many now use more cost-effective MLC (multi-level cell) flash. You can use either SLC or MLC as long as they are enterprise-grade SSDs.
  • Overprovisioned space. Writing to an SSD is a time-consuming task if data already exists in the flash. This is called a “program/erase cycle.” Also, cells in the flash can fail over time, creating the demand for new cells. These are two reasons why SSDs are overprovisioned and have more memory than what's presented to the system. That overprovisioned space is used to maintain high levels of performance and to replace cells that have failed. Enterprise-grade SSDs often have a higher level of overprovisioned space, increasing performance and extending the life of the SSD.
  • SSD controller. The controller inside the drive is often different for enterprise and consumer-grade SSDs. Enterprise drives are tuned more for extended use to handle more write cycles and use reclamation features such as TRIM and UNMAP* to be alerted and data removal by the system to optimize capacity and performance.
  • SATA vs. SAS. Similar to HDDs, SSD drives are available with SATA or SAS connectivity. The Drobo B1200i will support both SATA and SAS drives, but enterprise-grade SSDs are only available with SAS connectivity.

Consult the compatibility list for supported SSDs to use in the B1200i.

*In computing, TRIM and UNMAP commands allow systems to inform a solid-state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally.

Solid State Drives (SSDs) for the Drobo 5D, Drobo 5N and Drobo Mini:

The Drobo 5D, Drobo 5N, and Drobo Mini support SSDs as well as HDDs. A few things to consider if you want to use SSDs in one of these new Drobos:

  • Compatibility. While Drobos are designed to support a wide range of drive options, not all SSDs are the same. Make sure you check the SSD compatibility list to ensure that the drive you're considering works with your Drobo.
  • Form factor. Most SSDs come in a 2.5" drive form factor. While this is fine for Drobo Mini, Drobo 5D and Drobo 5N have 3.5" drive bays. To use a 2.5" SSD in a 3.5" bay, a carrier is needed.
  • mSATA. Drobo 5D, Drobo 5N, and Drobo Mini have an additional drive bay on the bottom of the chassis, the Drobo Accelerator Bay, to accept an mSATA SSD. This gives you the performance of an SSD to make reading small and randomly accessed data much faster while still maintaining the high capacity of HDDs. Using an mSATA SSD with HDDs in the standard drive bays is an ideal configuration for the new Drobos.

Consult the compatibility list for supported SSDs to use in the B1200i.

Popular Drive Configurations:

The new Drobo B1200i, 5D, 5N, and Mini models all support SSDs as well as HDDs. While Drobo will work with most drive combinations, below are common and recommended drive configurations to consider.

Drobo B1200i

While planning to deploy one or more Drobo B1200i storage arrays, consider the following configuration scenarios. Note that 6 HDDs is the minimum supported configuration and fewer than 6 HDDs is not recommended.

6 x 7200 RPM HDDs, 12 x 7200 RPM HDDs and 3 x SSDs + 9 x 7200 RPM HDDs
6 x 7200 RPM HDDs:
  • For lower-tier storage
  • For file storage, backup, and so on
  • Tested IOPS, 4K random read = 704 IOPS
  • Tested throughput, 512K sequential read = 273 MB/sec
Advantage = Leaves empty drive bays to expand capacity seamlessly as you grow
12 x 7200 RPM HDDs:
  • For lightweight business applications or lower-tier storage
  • Tested IOPS, 4K random read = 1008 IOPS
  • Tested throughput, 512K sequential read = 314 MB/sec
Advantage = Maximum storage capacity (> 38TB of available capacity if all 4TB drives)
3 x SSDs + 9 x 7200 RPM HDDs:
  • For Tier 1 applications and server virtualization
  • Tested IOPS, 4K random read = 2365 IOPS
  • Tested throughput, 512K sequential read = 361 MB/sec
Advantage = High performance plus high capacity


Drobo 5D and 5N

While planning to deploy a Drobo 5D or 5N storage array, consider the following configuration scenarios.

Drobo 5D and 5N HDDs only and SSDs only Drobo 5D and 5N HDDs with mSATA SSD
HDDs only:
  • 2 HDDs required
  • 3 open drive bays for expansion
  • Drobo Accelerator Bay open for performance boost
Advantage = Highest capacity, best price per TB of storage
Disadvantage = Slower performance compared to SSDs
SSDs only:
  • 2 SSDs required
  • 3 open drive bays for expansion
  • Drobo Accelerator Bay open for performance boost
Advantage = Highest performance
Disadvantage = Most expensive, lowest capacity
HDDs with mSATA SSD:
  • 2 HDDs required
  • 3 open drive bays for expansion
  • mSATA SSD in Drobo Accelerator Bay
Advantage = Highest capacity, best price per TB of storage, SSD accelerated
Disadvantage = Very fast, but not as fast as using all SSDs


Drobo Mini

While planning to deploy a Drobo Mini storage array, consider the following configuration scenarios.

Drobo Mini HDDs only and SSDs only Drobo Mini HDDs with mSATA SSD
HDDs only:
  • 2 HDDs required
  • 2 open drive bays for expansion
  • Drobo Accelerator Bay open for performance boost
Advantage = Highest capacity, best price per TB of storage
Disadvantage = Slower performance compared to SSDs
SSDs only:
  • 2 SSDs required
  • 2 open drive bays for expansion
  • Drobo Accelerator Bay open for performance boost
Advantage = Highest performance
Disadvantage = Most expensive, lowest capacity
HDDs with mSATA SSD:
  • 2 HDDs required
  • 2 open drive bays for expansion
  • mSATA SSD in Drobo Accelerator Bay
Advantage = Highest capacity, best price per TB of storage, SSD accelerated
Disadvantage = Very fast, but not as fast as using all SSDs