Original Source: www.pcper.com
Introduction and Packaging
Data Robotics shipped their first product 10 years ago. Dubbed the Drobo (short for Data Robot), it was a 4-bay hot-swappable USB 2.0 connected external storage device. At a time where RAID was still a term mostly unknown to typical PC users, the Drobo was already pushing the concept of data redundancy past what those familiar with RAID were used to. BeyondRAID offered a form of redundant data storage that decoupled rigid RAID structures from fixed capacity disk packs. While most RAID volumes were ‘dumb’, BeyondRAID was aware of what was stored within its partitions, distributing that data in block format across the available disks. This not only significantly speed up rebuilding (only used portions of the disks need be recopied), it allowed for other cool tricks like the ability to mix drive capacities within the same array. Switching between parity levels could also be done on-the-fly and with significantly less effort than traditional RAID migrations.
While all of the above was great, the original Drobo saw performance hits from its block level management, which was limited by the processing overhead combined with the available processing power for such a device at the time. The first Drobo model was lucky to break 15 MB/s, which could not even fully saturate a USB 2.0 link. After the launch, requests for network attached capability led to the launch of the DroboShare, which could act as a USB to ethernet bridge. It worked but was still limited by the link speed of the connected Drobo. A Drobo FS launched a few years later, but it was not much quicker. Three years after that we got the 5N, which was finally a worthy contender in the space.
10 years and nearly a dozen models later, we now have the Drobo 5N2, which will replace the aging 5N. The newer model retains the same 5-bay form factor and mSATA bay for optional SSD cache but adds a second bondable Gigabit Ethernet port and upgrades most of the internals. Faster hardware specs and newer more capable firmware enables increased throughput and volume sizes up to 64TB. Since BeyondRAID is thin provisioned, you always make the volume as large as it can be and simply add disk capacity as the amount of stored content grows over time.
The 5N2 sits at the higher end of the consumer Drobos, just below the much higher end 8-bay models, but don’t let the 5-bays fool you. The 5N2 actually borrows many of the features of the B810n.
The biggest feature here is dual Gigabit, and what makes it so great on Drobos is their seamless implementation of channel bonding, which effectively doubles the possible network throughput. While you are still limited by the Gigabit link of destination systems on the network, multiple streams to separate computers or to a single 10 GbE system will see significant improvements to transfer speed.
Drobo has always been pretty good about supporting migration from older hardware, and while their list of NAS-type devices is a short one, they do support migrations to the new 5N2, with a few notable caveats. While you can simply shut down your old Drobo FS or 5N and move your disk pack over to the new 5N2 and be back up and running within a few minutes, the older file system formats used on those units are not in-place migratable and will incur a 25% performance penalty. This only applies to older 16TB-limited volumes – if you created a volume more recently on a 5N with newer firmware (3.5.0 and up), you can avoid this concern. The differences between the old and new file systems stem from BeyondRAID improvements coupled with a shift from ext3 to ext4 for the base file system, and unfortunately the only way to upgrade to the newer format is to set up the 5N2 with a fresh set of disks and copy your files over from your older FS/5N prior to decommissioning it.
Speaking of upgrading, Drobo is offering a $50 discount on the 5N2 to Drobo FS and 5N owners. The offer is valid through April 4, 2017, via drobostore.com.
The Drobo unboxing experience is always simple and straightforward.
Simple notes, links, and quick start guides get you up and running quickly.
The drive light guide now comes in a few additional languages.
Before moving onto the setup process, here’s a look at the underbelly mSATA slot. Like the drive bays, installation is completely tool-less.
Setup, Configuration, and Features
This is always dead simple with a Drobo. Install drives, plug in and attach cables, power on, and let ‘er rip.
While the 5N2 is powering up, you should download and install the Drobo Dashboard app. This is the app that handles firmware updates to the 5N2, and you should ensure you are on the newest firmware before setting up your volume. Once the firmware is up to date, volume creation is automatic. Here we see the status after the volume has been created. Note that not all options are available while the volume setup is completing its initialization.
Once the initial setup process is complete (~20 minutes), the Drobo is ready to go and you gain access to the rest of the menu structure. Digging into some of the stats, we see just under 29TB of space available using the default single redundancy (RAID-5) mode.
Share settings are comprehensive and about what you’d expect for a NAS product.
Enabling additional features such as DroboDR (Data Replication) and DroboApps requires the setup of an administrator login and password in order to protect the device configuration. This is a good idea even if you don’t intend to use either of those features.
DroboApps are services that can be installed and run on the 5N2 itself. Here is a full list current as of this writing:
These apps add all sorts of functionality to the Drobo 5N2. DroboAccess is their own encrypted remote access (we tested it a few months back). There are file sharing, web serving, code management, media streaming and collection apps. For those so bold and capable, you can even make your own.
The ‘Drobo Settings…’ option at the left brings up a submenu of items, the first of which is General Settings. Here you can enable dual disk redundancy (RAID-6) with the check of a box. This prompts with a warning that available capacity will be reduced. In the 5x8TB config we were running, the prompt noted the available capacity would be reduced to 21.79TB.
Migration takes some time, as an additional level of parity must be calculated and written across the disks. That said, migrations tend to be significantly faster than traditional RAID, as only the stored data must be processed.
Now for the cool part. Under network settings, we have a simple looking check box to enable Network Interface Bonding. Those in the IT field reading this may be a bit agitated at how simple this is (compared to their own experiences with NIC teaming / link aggregation). While the 5N2 is capable of acting as a NAS on two separate networks, enabling NIC Bonding means both GbE ports must be connected to the same network/switch in order to work properly and at full (potentially double) speed. I know you probably want to know if and how well this works, so let’s get straight to our look at performance.
Performance, Pricing, and Conclusion
For performance testing the 5N2, we went with a low-tech approach involving file copies to and from the unit across our LAN. The switch used was an older Netgear JGS524v1 unmanaged switch. For variety and additional data points, the two PCs were running Windows 8.1 and Windows 10. With 5x 8TB WD Reds installed and with Network Interface Bonding *disabled*, this is an example of a file copy to the 5N2 from two different systems on our network:
Standard single NIC configuration, simultaneous copy from two systems to 5N2
Note the total Gigabit throughput (112.1 MB/s) must be split between both systems. This is what you would typically see with any single GbE connected NAS. Now let’s see what happens after we check the Network Interface Bonding box in the 5N2’s configuration (note: this requires the 5N2 to reboot for this low-level change to take effect).
Bonded NICs, simultaneous copy from two systems to 5N2
And with that simple change, we are up to 176.1 MB/s, though it does bounce around a bit, as we are running up against throughput/latency limits of BeyondRAID plus relatively slow 5400 RPM NAS drives due to writing two files simultaneously.
Bonded NICs, simultaneous copy from 5N2 to two systems
Since HDDs can’t buffer reads as well as they can buffer writes, reading two separate files simultaneously sees even slower speeds, though we are still doing better than the ~50 MB/s we would see to each system without Bonded NICs at play.
Bonded NICs, simultaneous copy from 5N2 to two systems (reading the same file)
To show that it is the disks that are the limit here, two systems accessing an identical file fully saturates both links simultaneously. What we can tell here is that the network is not the bottleneck and that Drobo’s NIC bonding implementation is working quite well here.
Bonded NICs, simultaneous copy from 5N2 to two systems (mSATA cache installed)
Having an mSATA SSD installed helps with these simultaneous file reads, as well as with random reads overall, as the Drobo can keep an extra copy of selected content on a very low latency device. Those wanting improved mixed workload and small random performance can also skip the mSATA option and simply install SATA SSDs in place of HDDs. Costly indeed, but certainly doable and supported.
Bonded NICs, single copy from 5N2 to single system after large file deletion
It is worth noting that since Drobo keeps itself aware of the contents of its volumes, file deletions and other activity may lead to some background cleanup and garbage collection of unused BeyondRAID data blocks. During testing, I was able to trigger one such cleanup event, which became apparent as the drives were busy thrashing a bit during one of the subsequent copy attempts. Note that faster drives, the mSATA cache, etc. will help these operations complete more quickly. I don’t see this as a major issue – just something to be aware of before performing large operations while expecting full speed response to other users.
Bonded NICs, simultaneous copy from two systems to 5N2 (5x 160GB VelociRaptor)
Above is a repeat of the second test from earlier on this page, but this time I swapped in a set of WD VelociRaptors in an attempt to evaluate the sensitivity of seek times on multi-stream performance. As you can see, things improved considerably. We are now up to 186.2 MB/s combined throughput. The drives we swapped in had lower sequential performance than the 8TB Reds, but faster seeks, meaning they could more quickly toggle between the pair of streams being applied here.
The Drobo 5N2 is priced at $499 and is currently available for order direct from drobostore.com. There are a couple of promos running until April 4th, 2017:
- $50 discount to prior Drobo FS and 5N customers
- US customers get a free GelaSkin with their 5N2 purchase
This price is actually pretty good considering the other 5-bay solutions currently on the market. Synology products do include some additional flexibility and connectivity (you can connect additional external HDDs via USB, etc), but the BeyondRAID flexibility and simpler configuration of the Drobo are definitely appealing to some.
Drobo’s 5N2 combines their long-standing tradition of dead simple setup and configuration with increased speed through a pair of bonded Gigabit Ethernet interfaces. Bonding takes the 5N2 from a device that can perform solidly on two separate networks to one that can offer almost twice the performance on a single subnet. While Drobo increased the processing capability to support the additional network throughput, we were beginning to encroach upon the seek performance of NAS-grade HDDs when attempting to serve two simultaneous Gigabit streams. DroboApps has grown to cover the majority of things you would possibly want to run on a home NAS, and DroboDR offers off-site backup (to another Drobo). Overall, the combination of Drobo’s BeyondRAID, bonded Gigabit Ethernet, 5 drive bays, and a competitive price point, make for a compelling NAS package worthy of serious consideration for any home or small business network storage needs.
After several prior ‘N’ Drobos falling short of our expectations, the 5N2 is a good performer at a great price, and it becomes my default recommendation for a 5-bay NAS.