Performance, Price, and ConclusionPerformance
*correction*: This chart originally stated eSATA in place of iSCSI. This was in error and has been corrected.
We saw maximum read throughput over iSCSI with as low as 3 drives installed. The same maximum speed was attainable using either single or dual redundancy modes, proving the pair of Marvell ARM processors is able to crunch the data faster than even the iSCSI interface can move it. iSCSI throughput showed itself to be fairly close to maximum theoretical iSCSI throughput over Gigabit.
There were scenarios where writes dropped lower than anticipated. These situations were found to be the result of data not being evenly spread across the installed drives. Since Drobo’s metadata system does not require a full rebuild upon adding a new drive, it will bias its writes after you add a new one to the mix, favoring it on new writes. As a result, write speeds may drop to as low as that of the emptiest (newest) drive until everything gets leveled out again, at which time writes return to the limits noted above. The lowest I could get write speeds was 35 MB/sec – caused by adding a 250GB drive to a nearly full set of 5x2TB drives. Writes returned to normal after moving enough data for the DroboPro to properly utilize the added 250GB unit.
We noted reads and writes to take a very small hit if healing was taking place. The DroboPro was pretty good about keeping background activity out of the way.
DroboPro lists at $1499 for the bare model. They offer the units for sale direct from their web site, along with multiple combo deals including various hard drive sizes. Some of the combo deals, as well as the bare unit, can be found around the web for a few hundred less. Some quick math revealed they appear to be passing along the hard drives at very close to cost, leaving their only mark-up limited to the unit itself. Some may prefer the bundle deals as they eliminate some of the hassle and may make corporate buyers lives a bit easier as they can spec out and order the whole unit ready to go from one source.
Drobo occasionally run rebate promotions on their products. There was a $100 rebate on DroboPro from 14-30 SEP, and at this writing there is a $60 rebate on DroboPro (until 30 November). Kudos for putting the rebates right on their own site instead of making users hunt for them. While researching the rebates I discovered they are provided in the form of a pre-paid credit card. This can be either good or bad, depending on your preference. Money is money as far as I’m concerned.I know, don’t tell me. $1499 is pretty steep considering that is the price before adding any drives. I admit I cringed a bit at the cost when I first saw it. After some analysis of what I’ve spent on my own RAID solutions over the years, that price starts to not seem so bad. Consider a rough outline of a system that would be spec’d with functionality similar to that of the DroboPro, but using off-the-shelf hardware. I did just that, surfing for what I would consider using in a hypothetical system, and trying my best to match the hardware features of the DroboPro.
|Case||Antec 900 with 2x 4-bay hot swap: $270||8-bay external: $319 – $679|
|RAID card||Areca ARC-1220: $440||Areca ARC-1221x: $580|
|Battery Back Up||Areca ARC-6120: $110||Areca ARC-6120: $110|
|System||PCPer HW Leaderboard ‘Budget’: $548||PCPer HW Leaderboard ‘Budget’: $548|
The above setups, even equipped with high-end RAID hardware, are lacking in that no hardware RAID cards employ BeyondRAID and are therefore unable to ‘switch on the fly’ like the Drobo units can. You would not get the convenience of cage-less hard disk swaps (i.e. no tools required). The above units also significantly lack portability and connectivity. The external units require an eSATA equipped system wherever they would be connected (with matching RAID hardware to properly mount the array), while the internal array could only be moved with the system enclosing it. I realize RAID setups can be done for less, but remember I had to go with a 72-hour rated battery backup unit to match that of the DroboPro, and was trying to get close to the fit and finish of Drobo as well. The ultimate throughput of the above configurations would exceed that of the DroboPro, as 8 parallel SATA channels can move data much faster than Gigabit Ethernet, but this is the only area where Drobo takes a back seat. That said, there are very few occasions where greater than GIG-e speeds are needed from this type of mass storage device. GIG-e throughput can handle the vast majority of home network needs (including that of some small businesses).
- Incredibly easy to use
- Included Dashboard software also very easy to use
- BeyondRAID adds too many features to even list here
- 8-bay storage in a compact and portable form
- Whisper quiet operation with thermally controlled fans
- Excellent transfer speeds over Gigabit Ethernet
- No eSATA
- Price is high (but you get what you pay for)
For its unique ability to satisfy both novices and power users
alike, as well as its ability to retain its data in the face of
dozens of sabotage attempts in our lab, I have no choice but to give the
DroboPro my highest recommendation in the area of redundant mass