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April 2018
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Data recovery of from Synology NAS (DS216)

Two disks taken from a Synology NAS DS216

NAS devices have never been so popular. They consume less power than a PC or server, they support RAID and their compactness means they can be stored in even the most space deprived homes or offices. While first generation NAS devices were basically conjoined hard disks with a built-in networking component, modern NAS devices are much more sophisticated. Most come equipped with their own operating system such as DSM (for Synology) or QTS as used by Qnap. Most NAS devices also support file sharing protocols such as SMB and NFS, which make them ideal for OS-agnostic environments.

Even though most NAS devices support RAID redundancy, it is surprising how many users forsake this safety net in lieu of performance by setting up their devices in a RAID 0 configuration.

Recently, we helped a user to recover files from his Synology NAS DS216 configured in RAID 0. Inside the array were two Western Digital Disks – a 1.5TB disk (WD15EARS) and a 2TB disk (WD20EZRX). Our diagnostics revealed that the latter disk had firmware issues. Once these were resolved, we imaged both disks. Using both disk images, we rebuilt the RAID 0 using its original parameters. The file system used was EXT4.
We recovered over 2TB of Final Cut Pro 9 (. fcp) files along with .MOV and.AVI files. – everything which the client needed.

In this case, the user made the mistake of using RAID 0 but can you spot the second mistake from the photo above? He also used two WD Green disks. For NAS devices, this is another common technical faux pas. “Eco-class” disks and many standard “desktop-class” disks do not support TLER (time limited error recovery) functionality needed to minimise errors on a RAID environment. “NAS-class” disks such as WD’s NASware disks or HGST’s Deskstar NAS disks are recommended. But perhaps the greatest step the user could have taken was to have his data backed up! Apps in Synology’s DSM facilitate this as well as third party apps such as BackBlaze B2 or using OS apps such as Resilio.