I have a MacPro with a corestorage LVG, with three physical drives: An SSD and 2 x 2TB drives. The fourth drive in the system was a Time Machine backup disk.
The backup disk and one of the 2TB drives both failed in quick succession. I cannot read any blocks from the two failed disks, tested using a FreeBSD system using SATA and a MegaRAID controller -- the disks don't respond to commands correctly so the issue doesn't seem to be a media issue.
I am assuming the data on these two disks is lost.
Booting from 10.11 USB installation key and running
diskutil cs list shows an LVG with a uuid and a offline status. There are three physical volumes listed, the first two are the good devices with a status of "checking", and the third is a UUID and "(No properties)".
Attempting to repair gives "Incomplete or inconsistent CoreStorage Physical Volume set".
Attempting to run
diskutil cs removedisk <dead-disk-uuid> gives "Not a valid CoreStorage Physical Volume UUID (-69777)".
Is a partial recovery of a corestorage LVG with a failed physical disk possible? Is there a way of removing the dead disk from the LVG and getting a (damaged) filesystem view?