ASM has internal I/O timers. If a disk consistently fails to respond within a threshold (e.g., _asm_io_timeout), the health checker marks it as a slow or hanging I/O resource.
System administrators are urged to investigate immediate storage integrity issues following an automated alert indicating that the ASM Health Checker has detected a new failure within the storage subsystem. asm health checker found 1 new failures updated
Once the underlying issue is resolved:
ALTER DISKGROUP <diskgroup_name> ONLINE ALL;
ALTER DISKGROUP <diskgroup_name> CHECK;
Then re-run:
asmcmd health check
The failure count should return to 0.
tail -100 $ORACLE_BASE/diag/asm/+asm/+ASM1/trace/alert_+ASM1.log
$ asmcmd health check
...
FAILURE: Disk group DATA – Disk DATA_0002 is offline
...