ORA-15281: not all specified disks were brought ONLINE
Cause: Some of the disks specified either experienced I/O errors while being brought ONLINE, or were simultaneously brought OFFLINE or dropped in another session, or were full.
Action: Query V$ASM_DISK or use ASMCMD LSDSK to determine which disks were not brought ONLINE. Inspect any additional error messages and the alert log to determine the exact cause. If some of the disks failed, either fix the cause of the failures or drop the disks. If some of the disks are full, either free space in the disk group or add new disks to the diskgroup.