How to check ASM disks in Oracle

Run connected to the ASM instance, or a database instance that can see the v$asm views.

set pagesize 2000 
set lines 2000 
set long 999 
col path for a54 
select name, path, header_status, total_mb free_mb, trunc(bytes_read/1024/1024) read_mb, trunc(bytes_written/1024/1024) write_mb from v$asm_disk;