This command allows Oracle ASM to automatically fix any errors it can, such as correcting broken metadata pointers or updating stale allocation tables. In practice, executing this command often resolves the alert entirely.
The potential causes for such an alert are numerous, ranging from the benign to the catastrophic. It could be a transient I/O error caused by a hiccup in the storage area network (SAN), or it could be the early warning sign of a physical disk sector corruption. In some cases, it may relate to a mismatch in ASM attributes following a patch or a configuration drift. Regardless of the root cause, the Health Checker acts as the canary in the coal mine. By flagging the failure before the database crashes or data is corrupted, it provides the invaluable commodity of time.
Oracle ASM includes an automatic health check feature that constantly monitors the health of ASM diskgroups and the underlying physical disks.
The system automatically launches targeted health checks based on the problem type: asm health checker found 1 new failures updated
If the disk is permanently failed, you must drop it. If it was a temporary glitch, you can try to bring it back online. ALTER DISKGROUP your_diskgroup DROP DISK disk_name; Use code with caution. To try and online a disk: ALTER DISKGROUP your_diskgroup ONLINE DISK disk_name; Use code with caution. 6. Run ASM Diskgroup Check
Log into your ASM instance via SQL*Plus ( sqlplus / as sysasm ) and run the following to see the status of your disks:
: Log into SQL*Plus as SYSASM and run SELECT name, state, type, total_mb, free_mb FROM v$asm_diskgroup; to find offline disks. Step 2: Common Root Causes This command allows Oracle ASM to automatically fix
First, log in as grid or oracle and connect to the ASM instance to check which diskgroup is reporting the issue.
The most common cause. If an ASM disk becomes inaccessible due to:
The message is a critical alert typically logged in the Oracle ASM alert log when the Automatic Storage Management (ASM) instance detects an issue that threatens the integrity or availability of a disk group . Typical Causes It could be a transient I/O error caused
SQL> SELECT run_id, name, check_name, start_time, end_time, status FROM V$HM_RUN ORDER BY start_time DESC;
The ASM Health Checker constantly audits the storage environment's structural and operational integrity. When it logs an updated failure count, it is usually responding to one of four common architecture failures:
If the health check failed due to an offline disk, restore it to the disk group. Identify the path of the dropped disk using v$asm_disk .
⚠️ For production systems, always run a manual CHECK first. Review the output. If the repair command risks data loss, Oracle will refuse to apply the repair. In that case, you must restore from backup or use advanced tools (such as RMAN block recovery).
You can force ASM to verify the consistency of a disk group to see if it clears the error or provides more detail: ALTER DISKGROUP CHECK ALL; Use code with caution. Proactive Tips to Prevent Future Failures
