ORA-15131: block string of file string in diskgroup

admin

ORA-15131: block string offile string indiskgroup string couldnot be read
Cause: A block could not be read because the disk containingthe block is either
offline or an I/O error occured while reading the block. If this is mirroredfile, then
all disks that contain a copy of the block are either offline or receivederrors.
Action: Repairthe affected disk and bring it back online. Refer to accompanying
error messages to determine which disk has failed.