Check status of ASM disks

set linesize 200
set pagesize 500
set colsep   " | "
col "disk_name"   format a30
col group_number heading group|number
col header_status format a15
col "group_name"  format a10
col path          format a40
select group_number,disk_number,mount_status,header_status,mode_status,state,os_mb,total_mb,free_mb,path
from v$asm_disk;