Re-scans, OS reboots, or sector size changes ( ORA-15085 ) on the SAN break the shared storage layer. 📋 Comprehensive Troubleshooting Guide
Intermittent loss of connectivity to the SAN/LUNs causes heartbeat timeout warnings (e.g., Waited 15 secs for write IO ).
Too many offline disks in the PST disable the read quorum, triggering a forced dismount.
Instant Fix for Oracle ASM Disk Failures When this error appears in the ASM alert log, it is usually preceded by underlying I/O dropouts or timeout warnings. This requires immediate DBA intervention to prevent data loss or complete cluster eviction. 🛠️ Root Causes of the ASM Failure Alert asm health checker found 1 new failures updated
Slow response times from the storage subsystem cause the Oracle ASM instance to drop the impacted disks.
# Locate your ASM Alert log using the ADRCI tool adrci> show alert -p "message_text like '%ASM Health Checker%'" Use code with caution. 2. Verify Your Current Disk Group Status
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. Re-scans, OS reboots, or sector size changes (
Run the following SQL query within the SQL*Plus environment of the affected ASM instance to identify the disk group's operational mode:
The disk group is normal; the issue might be confined to a single disk.
A manual or automatic rebalance may clear the problem if the disk group maintains redundancy. Check the background work status: Instant Fix for Oracle ASM Disk Failures When