How it Works

Drobo 5D and Drobo Mini: Performance Matters

Drobo Performance Test UI

Drobo 5D and Drobo Mini are the first Drobos for professionals designed from the ground up for high-performance applications. Based on BeyondRAID technology, Drobo storage arrays have always been easy-to-use and maintain. Now they include innovative Data-Aware Tiering so you don’t have to choose between capacity and performance—you can have both—with disk drives (HDDs) for capacity and solid state drives (SSDs) for performance!

While benchmarking gives you a good indication of how well a storage device performs for a controlled test, it is not a replacement for real-world performance. Benchmarks are nice, but real-world performance is everything—and real-world performance typically involved more varied and mixed workloads than typical one-dimensional benchmarks.

The new Drobo 5D and Drobo Mini have a unique ability to deliver very strong real-world performance because Data-Aware Tiering provides exceptional transactional performance in addition to, and without compromising,
streaming performance.

Transactional Performance Makes a Big Difference
Streaming Performance
Real-World Comparison

Performance varies based on the types of drives and number of drives installed and may change from one test workload to another. Affordable and available drives were used for the benchmarks noted below; we will continually update them as we update products and performance levels.

NOTE: Since there is no storage benchmarking tool available on OS X similar to Iometer to perform transactional and mixed-workload tests, we wrote our own and we call it “Drobo Performance Test.” You can see what it looks like at the top right and We will be making it available for everyone who wants to use it soon.

Transactional Performance Makes a Big Difference

While HDDs are good at reading and writing big data (large files, video, and so on) sequentially, they’re not good at reading and writing small, or transactional, data (small file, databases, and so on). While big data takes up a majority of a drive’s capacity, it’s the small data performance that affects us continuously. That’s why, for example, replacing the HDD in your computer with an SSD boosts performance so much. It makes small data move a lot faster.

Instead of just swapping all the HDDs in an array for SSDs, Drobo created Data-Aware Tiering, which allows HDDs and SSDs to work together in the same array, delivering capacity AND performance. This allows you to store a lot of photos, video, music, and other media-rich data, and have very fast access to them. For example, if you store music in iTunes or photos in Adobe Lightroom, those files are controlled by a database, which is “small data” and very transactional in nature. The Drobo 5D and Drobo Mini are much faster at handling transactional workloads than previous generation Drobos and other competitive products on the market today.

Transactional performance is measured in the number of I/Os per second (IOPS) a storage device can handle. For example, if the computer is writing data to a storage device and ...

Each transfer, or I/O, is 4KB in size
Current performance is 5MB per second
The device is handling 1280 IOPS (5*1024/4)

Drobo 5D

When small data data is read frequently from a Drobo 5D, it is flagged as “hot” and is moved onto the mSATA SSD installed in the Accelerator Bay on the bottom of the device. You can see in the graphs below that within minutes, data starts migrating to the SSD to increase performance from under 400 IOPS to just under 1200 IOPS (4x – 12x faster than the transactional read rates for the Drobo S). This is not possible when using just standard disk drives or in competitive systems that do not have data-aware tiering.

Transactional writes are also significantly higher in Drobo 5D than Drobo S (10x - 12x) because of the way Data-Aware Tiering uses the HDDs.

Drobo 5D Transactional Reads Drobo 5D Transactional Writes

Drobo 5D with five 2TB Seagate Barracuda disk drives and one 32GB Crucial M4 mSATA SSD connected to a MacBook Pro 15” running OS X 10.8.2 using Thunderbolt. Read test – 4KB I/Os,
100% random. Write test – 4KB I/Os, 100% random. (Drobo Performance Test)

Drobo Mini

Just like on the Drobo 5D, frequently read data is flagged as “hot” and is moved onto the mSATA SSD. You can see that within minutes, data starts migrating to the SSD to increase performance from under 400 IOPS to just under 1200 IOPS.

Transactional writes are higher in Drobo Mini than Drobo S because of the way Data-Aware Tiering uses the HDDs, even with one less drive. Transactional writes are lower than Drobo 5D because the Mini has one less drive and because of the performance difference between 2.5” and 3.5” desktop-grade drives.

Drobo Mini Transactional Reads Drobo Mini Transactional Writes

Drobo Mini with four 750GB Seagate Momentus disk drives and one 60GB Drobo-specific OCZ Deneva 2 mSATA SSD connected to a MacBook Pro 15” running OS X 10.8.2 using Thunderbolt.
Read test – 4KB I/Os, 100% random. Write test – 4KB I/Os, 100% random. (Drobo Performance Test)

Drobo S

While Drobo S performed well streaming large files, it was not as good at reading and writing small data quickly.

Drobo S Transactional Reads Drobo S Transactional Writes

Drobo S with five 2TB Western Digital RE4 disk drives connected to a MacBook Pro 15” running OS X 10.8.2 using USB 3.0. Read test – 4KB I/Os, 100% random. Write test – 4KB I/Os,
100% random. (Drobo Performance Test)

Comparison with a Competitor’s Thunderbolt Array

All Thunderbolt arrays are fast at moving large amounts of data, but moving small data efficiently, consistently, and without compromise is a different story. In this example, the competitor’s array supports only HDDs, so transactional read performance hovers just under 400 IOPS (shown in the graph on the left) because that’s all HDDs can do when they’re not supplemented with an SSD.

The competitive array that was tested has a large amount of write cache, so it can accept transactional writes in bursts, but then when it has to empty that cache to disk, performance drops significantly or even stalls. Overall, real-world performance is choppy and uneven as shown in the graph on the right.

Competitor Thunderbolt Array Transactional Reads

Competitive Thunderbolt array with five 1TB Hitachi Deskstar disk drives connected to a MacBook Pro 15” running OS X 10.8.2 using Thunderbolt. Read test – 4KB I/Os, 100% random.
Write test – 4KB I/Os, 100% random. (Drobo Performance Test)

Streaming Performance

Most storage devices are benchmarked on their streaming performance, or how fast they can move large amounts of data sequentially. The new Drobo 5D and Mini are significantly faster at streaming than past-generation Drobos. And while all Thunderbolt storage devices are fast at streaming, many falter when faced with real-world combinations of streaming and transactional performance.