Can a 12-year-old RAID 6 be recovered when all 300GB 10k SAS drives have crashed as a result of power outages?
What do 12-year-old 300GB 10k SAS HDDs look like after a head crash?
Not the way they should!
Instead of a shiny, smooth, mirrored finish, it can look like the grooves of a vinyl record have been scored into the protective layer and through to the recording layer, with debris from the heads and platters spread around all the internal surfaces of the drive.
All have varying levels of platter damage, resulting in unreadable sectors in different areas of each disk needed to rebuild the RAID 5.
Despite the catastrophic levels of damage, enough of each disk has been read to rebuild the RAID 5, but it cannot be perfect despite parity/redundancy.
The single RAID 5 volume hosts a number of VMs.
One of the VMs is all but perfect - the O/S.
The second VM has the critical SharedDataFolder containing the files needed by the client.
The VM file itself, its file system, and individual files are affected by the unreadable sectors drilled down into individual files.
As a percentage of the data in numbers and size, how much of the data was unrecovered?