Intermittent loss of connectivity to the SAN/LUNs causes heartbeat timeout warnings (e.g., Waited 15 secs for write IO ).
After verification, if a corruption is confirmed, you can attempt to repair it automatically:
(e.g., ORA-15xxx) is shown in the alert log? What is the output of SELECT * FROM v$asm_check_failure; ? asm health checker found 1 new failures updated
While Oracle performs default health checks, you should also schedule custom checks on a weekly or monthly basis. Use a script that runs ALTER DISKGROUP ... CHECK ALL NOREPAIR and logs the output for review.
In effect, the ASM Health Checker acts as a built‑in, automated diagnostics tool that confirms whether your storage structures remain healthy without waiting for user queries to hit a corrupted block. Intermittent loss of connectivity to the SAN/LUNs causes
: A LUN or physical disk has become inaccessible due to storage network (SAN) or hardware failure.
One disk was lagging, its I/O response times ballooning into the hundreds of milliseconds. While Oracle performs default health checks, you should
Use SQL*Plus connected to the ASM instance to identify which disk group or disk is involved.
Before making any changes, retrieve the trace file that corresponds to the background error. Look for lines right above the alert in your ASM alert log to identify the specific RBAL or GMON background trace file.