For small business owners like photographers, graphic designers, or other creative professionals, one hard disk failure (let alone two) is never anticipated on the day’s busy agenda, not to mention the wasted time and data loss. When a drive fails in a traditional RAID system, most will enter a state where data loss occurs if another drive fails before the user replaces the initial faulty drive. With Drobo’s BeyondRAID® technology, the Dual Disk Redundancy feature protects your data and allows up to two hard disks to fail on your Drobo by allocating space across the remaining drives in the array. Drobo will automatically re-layout the data to rebuild the array to the remaining working drives with no user interaction needed, and complete that same process again once you replace the failed drives with new ones.
Balancing your need for maximizing data storage capacity with this added protection should be taken into consideration when enabling Dual Disk Redundancy. Because more capacity is specifically reserved for protection across the array, your Drobo will have less usable space available for all those photos, files, and videos you’ve collected. Using our handy Drobo Capacity Calculator will show the remaining space left for data after enabling Dual Disk Redundancy, and also making sure your next upgrade takes advantage of larger hard drive sizes will give you more space as your digital library grows.
Along with enabling Dual Disk Redundancy to protect data against drive failures, you should always make sure you’re using optimized hard drives for your Drobo to keep up with your specific applications and use cases. Before purchasing, be sure to reference our online drive selector that will recommend the best type of hard drive or solid state drive for your direct attached, NAS, or SAN Drobo system, plus help balance your price and performance needs.
Terry White’s Tech Blog Take
In his recent blog post, Adobe’s Principal Worldwide Design & Photography Evangelist Terry White discusses why he choose to enable Dual Disk Redundancy on both his Drobo 5D and 5N, one used as main office storage and one as a backup target:
“Like you, my data is very important to me. I have several backups and offsite cloud backups too. In my home office I use a Drobo 5D connected to my Mac OS X Server as well as a second Drobo 5N to backup the Drobo 5D. The whole reason to have a Drobo is so that if one of your hard drives fail your data will be protected and you can just keep working. You’ll probably replace the failed drive with a larger one since larger drives come out every year. The one thing we don’t really think about is what happens if two drives fail at the same time? Normally this means you’re screwed and it would be time to restore from a backup (after replacing the two failed drives). The last time I had a Seagate 3TB drive die in my Drobo 5N, I not only replaced it with a WD 4TB NAS drive, but I also enabled Drobo’s dual redundancy feature in the settings.”
“When you setup your Drobo (RAID), chances are you bought multiple drives at the same time. So if one fails (especially as they get older), then it’s likely that another one bought around the same time could fail shortly thereafter. As a matter of fact I now know this can happen. Although I had turned on Dual Redundancy on my Drobo 5D, I had not yet turned it on my Drobo 5N. While traveling on business I received an email alert that one of my drives had failed (an older 2TB Seagate). No big deal as my data was protected. However, by the time I got home several days later a second 2TB Seagate drive had failed. That’s it. Game over. It wasn’t a huge deal since this Drobo served as a backup to my main Drobo. I didn’t lose anything other than Time Machine history.”
“Yes two drives can fail at the same time or back to back. While enabling Dual Redundancy does give you less storage space, drives are relatively cheap and it’s better safe than sorry.”
How to Enable Dual Disk Redundancy
Now that you’ve heard about the benefits, we’ll walk you step by step through the process for setting up this feature on your Drobo, which can be easily enabled in Drobo Dashboard on all current Drobo devices Gen 3 and above. If you have three or more drives installed, you can turn on Dual Disk Redundancy with these simple steps:
For Drobo Dashboard versions less than 2.0
Click Advanced Controls → Tools in Drobo Dashboard.
Within the General tab, check the box for “Dual Disk Redundancy”.
For Drobo Dashboard 2.0 or later
In Drobo Dashboard, select the appropriate Drobo device from the “All Devices” page.
Click Settings from the Navigation menu, and then click General.
Check the box for Dual Disk Redundancy.
When you check the Dual Disk Redundancy option in Drobo Dashboard, the lights on the unit flash and you are still protected against a single hard disk failure until the background work (called re-layout) is completed and the lights stop flashing, at which point you are protected against two disk failures. If you deactivate the Dual Disk Redundancy feature, your Drobo device immediately goes into single disk redundancy mode. You can still use your Drobo storage device normally, but the re-layout process might take quite a bit of time, depending upon how much data is on the device. Now you can sit back and have peace of mind knowing your data is safe against those unsuspecting simultaneous hard drive failures.