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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 TypesSupported Drive Types:

Drobo let's you take advantage of mix and matched drives to maximize your storage capacity and minimize up front investment and costs over-time. While the Drobo Mini utilizes small form factor 2.5" drives the rest of the Drobo products use the large form factor 3.5" drives. This guide will focus on the 3.5" drive and SSD technologies to help you select the right drives for your application, allowing you to balance acquisition costs and performance requirements versus capacity requirements.

Matching Drives to Your Application

Before deciding on which drive to choose, it is important to understand which drive types are best for your application. The table below shows which drive types are best suited by usage.

Drive Type Bulk Online
Storage
Back up File Sharing Media Editing Database
SQL/Exchange
Virtualization
Green SATA Yes Yes No No No No
Desktop SATA Yes Yes Yes Yes No No
NAS Optimized Yes Yes Yes Yes No No
Enterprise SATA Yes Yes Yes Yes No No
Enterprise/NL1 SAS No No Yes Yes Yes Yes
mSATA SSDs No No Yes Yes Yes Yes
Consumer SSDs No No Yes Yes No No
Enterprise SSDs No No Yes Yes Yes Yes

Notes: NL SAS or Nearline SAS drives have a SAS interface, but leverage the same head, media, and rotational speeds of traditional Enterprise SATA drives. They are ideal for Enterprise applications that have high capacity requirements.

Which Drives Should I Use?

Drobo’s BeyondRAID technology is designed to work with any drive depending on what is most important to you. Drives have varying cost, performance and reliability characteristics. Below is a recommendation of drive types by Drobo model:

Drive Type Green
SATA
Desktop
SATA
NAS
Optimized
Enterprise
SATA
Enterprise/
NL SAS
mSATA
SSD
Consumer
SSD
Enterprise
SSD
Drobo Yes Yes Yes Yes No No No No
Drobo 5D Yes Yes Yes Yes No Yes2 Yes2 No
Drobo 5N Yes Yes Yes Yes No Yes2 Yes2 No
Drobo 800fs Yes Yes Yes Yes No No No No
Drobo 800i Yes Yes Yes Yes No No No No
Drobo B1200i Yes Yes Yes Yes Yes No No Yes3/4

Performance

Notes:

  1. Consult the Drobo.com Knowledgebase for a list of mSATA SSDs and SSDs with the corresponding 2.5″to 3.5 converters that are qualified with the Drobo Mini, 5D and 5N.
  2. Consult the Drobo.com Knowledgebase for a list of Enterprise SSDs and the 2.5″to 3.5″converters that have been tested and qualified for use in the B1200i.
  3. Configuration note for B1200i: If being used for running databases, or hosting virtual machines, a minimum of six (6) hard drives and (3) SSDs is recommended.

Note on Drive Performance: For optimal performance, it's best not to mix drives that have different rotational speeds (RPM). Faster spinning drives will maximize total system performance. Leveraging SSD technology for caching, tiering or as primary storage will provide the best performance when deployed as recommended.

Below is a list of popular SATA Hard Drive models and how they are categorized

Drive Type Green SATA Desktop SATA NAS Optimized Enterprise SATA
HGST Deskstar No Yes No No
HGST Ultrastar No No No Yes
Seagate Barracuda Green Yes No No No
Seagate Desktop No Yes No No
Seagate Barracuda No Yes No No
Seagate NAS No No Yes No
Seagate Constellation No No No Yes
Seagate Terascale No No No Yes
Toshiba DT01ACA Series No Yes No No
Toshiba MG03Axxx Series No No No Yes
WD Green Yes No No No
WD Black No Yes No Yes
WD Red No No Yes No
WD RE No No No Yes
WD SE No No No Yes

Notes: 4K sector drives are supported. Consult the Drobo.com Knowledgebase article describing 4K sector drive support for Drobo products.

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.

Solid State Drives (SSDs) for the Drobo 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