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Meet Drobo: A Data-Saving Robot
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1. Data Collection - Starting From Scratch, But What's Next?

You don't have to go to a computer shop anymore if you need a storage product. Even supermarkets around the corner offer external hard drives for USB interfaces. And it wouldn't come as a surprise if your local drug store did as well. You can get 500 GB (external) hard drives for less than $200. It seems like a perfect deal for everyone - or is it?

I'm afraid it is not that easy, as single drives come with a crucial disadvantage: They are immensely susceptible to defects, which means that if your hard drive dies, then your data will walk the plank as well. If you need more storage capacity, you can simply buy another drive; or you can get a top-notch storage device that can store it all. However, due to a still poor cost-per-gigabyte ratio we do not recommend getting a terabyte drive unless you really need such a large capacity.

Meanwhile, we have tested Silicon Image's new-generation 2 SteelVine technology, which enables cascading and interconnecting external hard drives to create a virtual storage volume. This allows users to create high-capacity storage structures, either with or without RAID.

You can effectively diminish the risk of a worst-case data scenario by using RAID configurations, where several hard drives are interconnected as an array. RAID 1 uses two hard drives and simply mirrors content; RAID 5 adds recovery information and distributes it across all existing hard drives. However, most of the external RAID boxes harboring multiple hard drives are rather expensive and oftentimes not flexible at all. If you have to change the RAID mode or increase storage capacity you might have to swap data again. Surely, there is no such thing as easy handling for the lowbrow user.

By accident, we found Data Robotics' Drobo on the Internet. Drobo is a storage box for up to four hard drives; you connect the device via USB 2.0. eSATA would have been wonderful indeed, but USB 2.0. also seems sufficient for the purpose. A main plus is how Drobo enables users to insert as many additional drives as they wish to safely upgrade capacity. Drobo makes sure that data organization is appropriate and all data is safe, Data Robotics says.

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2. Data Safety Made Easy

RAID Levels - A Short Overview

Popular storage solutions for on-line operation and permanent availability are based on RAID configurations. RAID stands for Redundant Array of Independent/Inexpensive Drives. You are able to reach distinct goals by configuring your RAID array in different ways. Improved data throughput is called RAID 0; distributing data across two drives in a stripe set. This configuration scales with as many drives as your controller supports, but bears no question of data safety, since all data will be lost in case only one hard drive dies.

RAID 1 provides you with increased data security. Data written on one hard drive will be mirrored onto the second drive in this configuration. Thereby, you can still access your data on the functioning hard drive even if the other one is failing. After the defective hard drive is replaced, the RAID controller will mirror your data onto the new drive to restore a safe system state.

In regard to data security, RAID 5 is definitely the most common RAID configuration. You will need at least three hard drives for RAID 5. User data and parity information will be distributed across the drives. RAID 5 helps to recognize errors and to recover data after a hard drive failure. However, RAID arrays are not very flexible if you want to change the configuration.

The Promise: Automated Data Safety Without Configuration Hassles

Data Robotics' Drobo is supposed to do all the configuration work for you. The manufacturer's objective is to offer simple and safe data storage without a difficult setup process. The company's Website offers a video featuring Drobo's functions. Data Robotics claims the device allows you to upgrade hard drive capacity without performance losses and latency, while it automatically completes configuration and setup tasks for the user.

Virtualizing Hard Drives

Data Robotics utilizes the principle of virtualization to avoid typical limitations of static RAID arrays. Drobo administers available storage dynamically, depending on the size of the installed hard drive. It is also possible to use hard drives with different capacities.

One drawback is how Windows Explorer will always indicate that Drobo has 2 TB of storage capacity - regardless of the actual size of the disks in the array.

3. Drobo - A First Date

Elegant Looks Both In Front And Behind

Box Contents And Finish

Drobo has a stylish black color and looks great on your desk. The $500-storage device comes with a power cable, power adapter, USB cable and a CD. The latter contains the so-called Drobo Dashboard in addition to numerous introduction videos explaining how to use your Drobo. Hard drives are not included, though.

4. Delivery Content Includes No Hard Drives

A front panel, attached with magnets, catches your eye first. Behind this panel you will find the rickety-looking hard drive bays. You don't need removable frames to equip Drobo with hard drives. Simply slide in any SATA drives into the device. Correspondingly simple is the ejection mechanism: A larger spring next to the SATA interface applies pressure onto the hard drive, which is held by a plastic noose on the other end. It would have been better if there were a front panel with hinges as well as metal nooses instead of plastic ones. Considering the hefty price, this would not have been too much to ask.

Though everything is manufactured solidly, you don't really dare to push against the plastic when ejecting hard drives. Metal rails at each side of the hard drive to help slide it into the bay would have been better. However, the device should be easy to use - and that definitely is the case here.

Using metal instead of plastic and adding a hinge would have helped. You get a good look at the status lights on the bottom and right side.

Connection And Set-Up

Drobo only comes with a USB 2.0 interface. In our opinion, an up-to-date device should at least offer an eSATA port as well. Today, eSATA becomes the default high-performance external storage connection on many motherboards. A bottleneck already looms ahead, given that USB offers much lower data transfer rates than eSATA does. Drobo would thus not be attractive for power users. Since Drobo is designed for home users and direct connections to your system, you will also have to live without a high-speed network connection.

Poor connection possibilities - USB 2.0 is as much as you get. However, the device is designed as DAS (Direct Attached Storage), and not as NAS (Network Attached Storage).

Drobo will run a self test after it is first connected and activated. As a consequence, the temperature-regulated fan will run full-speed for a short period of time, which makes some noise. While in operation, however, a low humming sound is all you will hear. It is definitely good to know that sufficient performance reserves are available for cooling purposes, so a completely equipped Drobo as well as all existing hard drives will not die from overheating.

Your system will recognize the device immediately after connecting it via USB, and will display it in your device manager as a USB mass storage device. Windows Explorer indicates the device has a storage capacity of 2,048 GB. However, this is the value Drobo always claims to provide, even when the device carries no hard drives at all.

5. Not A Lot To Choose From: NTFS And HFS Support

Windows has all you need to run Drobo, so you don't have to install the software that comes with it. But if you want to know how much storage capacity Drobo is actually providing and if Drobo is keeping your data redundant, you should install the Drobo Dashboard. Windows Explorer accurately displays hard drive storage use. To initialize and format Drobo's virtual hard drive in your hard drive manager, you need to insert at least one hard drive.

Choosing the file system is specified by the manufacturer. For now, Drobo supports NTFS or HFS. Using FAT32 is neither officially supported nor recommended by Data Robotics, but it happens to work in limited ways. Data Robotics says it also wants to add support for additional file systems over time. For the time being, Drobo will only work reliably with Windows and Mac OS'. Neither NTFS nor HFS support is stable under Linux.

Installed Dashboard: a single click helps you to keep Drobo's firmware up to date.

The Dashboard is an easy way to keep firmware updated, to format Drobo or to set up how responsive it shall be. In case you want to use several Drobos with your computer, it makes sense to have a control panel indicating their status. This way, you can identify individual devices.

6. The Data Robot In Action

Mixed Mode: No Trouble With Different-Sized Hard Drives

Using Drobo is easy. You can get started with only one hard drive inserted. This configuration does not provide any kind of data security, though. For a redundant data configuration, you will at least need two hard drives. But Drobo does not require hard drives of the same size. ABM (asynchronous balanced mode), with an 80 GB and a 160 GB hard drive, is just as feasible as it is to use three 250 GB hard drives.

It doesn't matter if you use hard drives of different sizes.

Utilizing hard drives of different sizes will also result in different usage capacities. With the Drobo Dashboard, you can find out how your hard drive capacity is exactly allocated.

Drobo's Dashboard provides information about the current utilization of available hard drive capacity...

...and indicates which slot carries which hard drive as well as any given redundancy.
7. How Does It Work? Background Check For Data Security

Drobo is based on VXWorks, which constantly checks available storage capacity in the background and distributes data across all inserted hard drives if necessary. This way Drobo makes sure that all your data will be safely stored on remaining hard drives in case one of the drives fails. To accomplish this task, Drobo divides available storage capacity into logical discs, which Drobo fills with data. In case a hard drive fails or is added, those logical drives are re-allocated. The data is then re-allocated to account for the missing drive. This process always takes place in the background and therefore users won't even notice. You can even access your data during the reallocation process. The system will only ask for user intervention if Dashboard or the status lights on the front tell you to do so.

Dashboard will notify and recommend counter-measures if you run out of storage capacity.

Status lights on the right-hand side of Drobo indicate the system status. Depending on LED color or flashing frequency, users will know which drive is failing, if everything is running smoothly or if hard drives can be removed or not. The blue LED line on the lower end of Drobo indicates the amount of data that is stored. Drobo can also be used without having Dashboard installed.

The fill level indicator and hard drive status are indicated.
8. Testing Drobo

A Promise Kept - With Certain Reservations

During our tests, Drobo lived up to the promises made by its manufacturer. It is no problem at all to use hard drives with different capacities. Drobo can also automatically re-allocate data storage to different disks in case a hard drive is removed.

However, we did find flaws. Drobo enters a stand-by mode as soon as the system shuts down. After we restarted our computer, one of the hard drives was not recognized, and we had to remove the failed hard drive to get the device up and running again. We have to mention that we had to listen to the hard drive noise to identify the malfunctioning hard drive.

After Drobo's storage capacity limit was reached during our tests, we removed the 320 GB-which was also the largest - hard drive in our array and put it back right away. But we were also unable to get the device to restore full redundancy thereafter. Throughout this, test we wanted to find out how the system would react if a hard drive were accidentally removed- which can happen when you exchange hard drives and inadvertently grab the wrong one.

Preexisting data security.
9. Testing Drobo, Continued

No redundancy for our data after removing the 320 GB hard drive - just what we expected.

Reinserting the accidentally removed hard drive did not have any effects on the non-safe status of our data.

Drobo indicated that the status of our data was secure, even after we deleted data to get some free storage capacity.

Drobo was revived after we added a hard drive to the fourth slot, which was still available. An estimated four-hour rebuilding process attracted our attention.

10. Test Configuration
System Hardware
Processor(s) 2x Intel Xeon Processor (Nocona core)
3.6 GHz, FSB800, 1 MB L2 Cache
Platform Asus NCL-DS (Socket 604)
Intel E7520 Chipset, BIOS 1005
RAM Corsair CM72DD512AR-400 (DDR2-400 ECC, reg.)
2x 512 MB, CL3-3-3-10 Timings
System Hard Drive Western Digital Caviar WD1200JB
120 GB, 7,200 rpm, 8 MB Cache, UltraATA/100
Test Hard Drive I Seagate Barracuda 7200.9 ST3500641
500 GB, 7,200 rpm, 16 MB Cache, SATA/300
Mass Storage Controller(s) Intel 82801EB UltraATA/100 Controller (ICH5)
Silicon Image SATALink SiL3512
Driver 1.2.0.57
Promise FastTrak TX4310
Driver 2.06.1.310
Promise SATA 300TX4
Driver 1.0.0.33
Networking Broadcom BCM5721 On-Board Gigabit Ethernet NIC
Graphics Card On-Board Graphics
ATI RageXL, 8 MB
System Hardware
Performance benchmarks c’t h2benchw 3.6
PCMark05 V1.01
I/O Performance IOMeter 2003.05.10
Fileserver-Benchmark
Webserver-Benchmark
Database-Benchmark
Workstation-Benchmark
System Software & Drivers
OS Microsoft Windows Server 2003 Enterprise Edition
Service Pack 1
Platform Driver Intel Chipset Installation Utility 7.0.0.1025
Graphics Driver Default Windows Graphics Driver

Performance

We equipped Drobo with four different hard drives (80 GB, 160 GB, 320 GB, and 400 GB) for our test with HD Tach (version 3.0.1.0). We received average sequential transfer rates of 15.7 MB/s (read) and 11.0 MB/s (write). Compared to other USB storage devices, Drobo doesn’t convince with high performance. However, most external hard drives don’t come with data security features like Drobo does. The average access time was 27.7 ms, which puts our data robot on an NAS-device level. In practice, this means that users need a lot of time if they want to store 500 GB on Drobo. We still think that Drobo’s performance is acceptable after all. Different software, which is easy to install for users, is supposed to provide a performance increase, according to Data Robotics.

11. Conclusion: Groundbreaking Technology - But Expensive

Though Drobo the data robot is easy to handle, well-manufactured and helps home users to administer and manage large amounts of data, we think it is still too expensive for a consumer device. With only a USB connection, Drobo clearly belongs in the home user segment. And home users will think twice before spending $500 on a Drobo unit.

Data Robotics emphasizes how customers can always buy drives with the best cost-per-gigabyte ratio, which is a strong argument. Another plus is how Drobo allows for an asynchronous hard drive configuration. But since a safe harbor for your data is actually what you're aiming for, those used 80 GB or 100 GB hard drives in your closet simply won't do the trick. So, you must add about $200 for two 400 GB hard drives to the cost of one Drobo unit to properly use the device.

Drobo represents a lot of money and many users might instead opt to invest in traditional, external hard drives and manual data backup. This is actually too bad, since we really like the idea behind Drobo despite its flaws. If you don't mind its high price and only average data transfer rates, Drobo is a storage device that needs almost no user intervention. It is also technologically groundbreaking.

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