- 1 x Drobo 5N
- 1 x Power cord
- 1 x Ethernet cable
Inside the 5N bundle you will find everything you to setup the device straight away. The front of the Drobo 5N features a sleek face plate, which is being kept in place by magnets. Taking off the black, plastic face plate gives you access to the five drive bays, which allow for tool-less installation of up to five drives. The front also comes with different LEDs, which indicate the status of each hard drive, inform about malfunction and monitor power.
Turning the Drobo 5N around shows that there is a 120mm fan. The fan is silent but not inaudible. We would love to see a Drobo use a more silent fan, which doesn't have any bearing noise. A closer look at this side of the devices shows one RJ45 Gigabit Ethernet port, the power button and one DC IN plugs for the power supply. As far as the hardware is concerned, the Drobo 5N is based on a Marvell 78460 embedded CPU. This particular model features four cores, clocks at 1.2GHz and comes with a built-in 2MB cache. Apart from that manufacturers have the possibility to attach devices via two x4 PCIe 2.0 channels, which means there is a total of eight PCIe 2.0 lanes available. Furthermore the processor supports 16 SERDES lanes, which offer PCI-Express, SGMII, SATA, QSGMII or ETM functionality.
In order to understand the advantages and also to a certain extent limitations, one needs to undstand the limitation of RAID arrays. In the case of a normal RAID array all drives need to be of the same capacity. In the example of a RAID1 with one 4TB and one 6TB drive, you will end up with an array capacity of 4TB, wasting 2TB. If you would like to change the RAID mode at a later stage you'll have to destroy the old array, losing all the data on your drives, to then create a new array. Apart from that there is another limitation, which concerns the physical migration of a RAID array. In such an event you would have to make sure that the drives are inserted in the same order the were in the old device, otherwise the array is not being recognized.
BeyondRAID from Drobo offers the possibility to combine drives of different sizes in an array. Depending on the security level you choose, either the loss of one or two drives is protected. If you wish to migrate your array to a new device, you will not have to make sure you're using the same drive order. BeyondRAID is capable of recognizing the array even if the drive order has been changed, which makes upgrading to a new device much easier. Yet another advantage of BeyondRAID is that the protection level can be changed on-the-fly, removing the necessity of destroying the array before switching the protection level.
Regarding limitations of BeyondRAID we have a quick look at how the protection issue is addressed, meaning how much parity data needs to be saved. This depends on the security level you choose. If you decide to enable single-drive-protection then the capacity of the largest drive in the array will be reserved. In the case of dual-disk-protection the capacity of the two largest drives will be reserved. In our case Drobo shipped the 5N with the following drives: 1TB, 2TB, 2TB, 4TB and 6TB. If we choose single-drive-protection then 6TB and in the case of dual-drive-protection 4TB+6TB, 10TB respectively will be reserved.
mSATA acceleration SSD
To increase performance Drobo equipped this unit with a nifty little feature. Sheer throughput and IOPS used to be the achilles heel of Drobo NAS for the consumer market. In combination with a quad core embedded CPU there is now plenty of calculation power, which allowed the implementation of SSD caching. If you wish to make use of this functionality you can flip the device over and access the mSATA SSD slot at the bottom. Once the drive has been installed and the 5N booted, it's automatically being configured. The whole process only takes a few minutes and then enables massively boosted IOPS performance and also the throughput performance benefits. When we wanted to try this feature we unfortunately weren't aware that not all mSATA SSDs are compatible and our SandForce SF-2281 based drive wasn't working. Therefore we strongly recommend to consult Drobo's compatibility
list before purchasing a mSATA caching SSD.
In a second article on the Drobo 5N we will have a close look at the performance difference, when adding a mSATA acceleration SSD. Especially in the case of IOPS performance we're expecting a huge boost, whereas the sequential throughput should be bottlenecked by the 1 Gigabit Ethernet interface.