To reconstruct an array we use file system structure, so if file system was wiped from array and then un-RAIDed, the only reasonable way to reconstruct such array is manual reconstruction. Otherwise, estimated recovery time will be many months.
Another problem with same consequences are RAID arrays with over 10 disks. At this case, there are 10! possible combinations, multiplied to 11 possible stripe sizes and 4 RAID geometries gives 159667200 sets to enumerate. Assuming your PC can calculate 1000 sets per second, would give estimated recovery time of 18,5 days.
This mode is used to reconstruct RAID automatically. To reconstruct RAID or dynamic disk choose corresponding setting and click “Next"
Select disk number and check disks from array.
RAID Recovery will attempt to detect RAID disks automatically. If it fails, you'll get the following message
and you'll be prompted to select RAID parameters manually:
Check either RAID level, or manufacturer of your RAID controller. The less options you'll check, the faster the scan. On the contrary, selecting too many options slows down the process a lot.
After possible configurations are enumerated
you should see this screen:
Actually this is Constructor window, which can be selected directly at the start of the Raid Wizard. You can check all detected configurations and edit them if necessary. All configurations checked at the left column will be added to the disk list after pressing "Finish". Please refer to Constructor section below to learn more about this tool.
When "Finish" is clicked, you should see following notification:
All RAID sets will be added to the disk list. Fresh added disks are marked red.
First of all you need to search for partition with a label of original RAID volume. If it was recovered, it should be at the “Hard disk drives" section. If partition table of the RAID disk was damaged you may encounter a “NT_mapped" disk with a size of original volume. This means it was not found at partition table, but recovered from disk.
NAS devices usually have 3 partitions: Linux swap partition, system partition and user data disk. The latter is the biggest of them all and almost equals to the total NAS size.
As RAID recovery was based on present file system, there is no need to open reconstructed disk in “Full Recovery" mode. Select “Reader" to access current data or “Uneraser" if you need to restore deleted file.
We recommend to check RAID disks by previewing a large picture 1-2 Mb to ensure if recovery was successful or not.
The image should be complete and have no visual defects.
Limitations of automated mode
If you set up too many parameters to be enumerated, following error message will appear:
During automatic reconstruction mode RAID Wizard enumerates all possible configurations. These are disk order combinations, stripe sizes and possible geometries. For example automatic reconstruction of RAID 5 that consists of 12 disks should check 12!(disk orders) * 4(geometries) * 10(stripe sizes) =19160064000 configurations. Assuming your PC is able to enumerate 1000 per second(which is quite optimistic supposition) it would require 2217.6 days to complete.
Developers can supply you with a custom build with this limit removed, however it won't reduce recovery time. At this cases best approach would be reconstructing RAID's configuration manually at the constructor or order our reconstruction service.