Recovering Data from a Failed Synology NAS
So, you have been running your Network Attached Storage (NAS) units continuously and it has now reached a point when the units fail and you can no longer access your data. What next? NAS is a means of data storage and it can be connected directly to a PC network. NAS units have no monitor or keyboard and are used only for storage of file-based data. These units are created using the Linux operating system drivers which have been installed on a small computer. They can also be created on the basis of dedicated chips which are comparable with a hardware RAID. When it comes to data storage, NAS usually uses the means of a regular RAID. This makes it subject to many failures, as is common for RAIDS. In cases of failures in the storage system, action taken usually depends on the type of implementation of the NAS unit.
NAS Recovery with the use of dedicated hardware
Rather than using tailored Linux, NAS can be run using a dedicated chip alongside its firmware. Although this type of NAS is almost extinct, we will still discuss this. Here, you may swap your drives into the same device. Extra care should be taken when using RAID 5 arrays as there are high chances that the disks could not be recognized by the controller which would begin initializing them. This would automatically lead to loss of your data. The second option is using the RAID recovery software, which has the capacity to reconstruct the RAID configuration. Here, you will be required to connect all member disks to a PC that has enough ports. Then start the RAID Recovery Software just like ZAR.
NAS recovery on the basis of Linux/mdraid
A majority of modern NAS units, such as those made by Synology, Net gear or QNAP, are special purpose PCs. When handling the RAID, these units make use of an Intel Atom or a similar CPU and an installation of Linux that is specifically tailored. Some components such as indicator LED arrays and SATA hot-swap backplanes are not found in regular PCs. However, the wholesome system closely resembles a regular PC. Smaller NAS units such as those having two disk bays make use of a system on-chip design, PPC or ARM processor. However, this is also controlled by Linux. Linux-based NAS units use standard mdraid drivers to offer the required raid capability and ext3/4 for the filesystem.
Since standard software is used, little effort is required when mounting disks from the NAS unit onto a Linux system. After mounting the disks onto the Linux PC, type the command ‘sudo mdadm –assemble –scan –assume-clean’ then see what it brings. This will offer a fast escape route in case of failure of the NAS. Should Linux not bring anything useful, then you can use the Data Recovery Software which has the capacity of processing all mdraid records.