For those of us who have broken arrays (parity invalid) and need to recover data disks there is "ddrescue". It was available in unraid V5 through unmenu. I'm not aware of it being available for unraid V6. It is critical that this is available when all other data recovery options fail. Could this please go into nerd pack?
wget http://slackware.cs.utah.edu/pub/slackware/slackware64-14.2/slackware64/ap/ddrescue-1.21-x86_64-1.txz
installpkg ddrescue-1.21-x86_64-1.txz