Oracle ASM Queries Every DBA Needs
Automatic Storage Management (ASM) is the heart of Oracle database storage. Regular monitoring helps prevent outages, balance I/O, and plan capacity effectively.
1. Diskgroup & Disk Health Check
Disk Group Space & Health
Disk Level Details — Most Important
2. Rebalance & I/O Monitoring
Current ASM Operations
I/O Balance Across Disks
3. File-Level & Template Insight
ASM Voting Files and Attribute Details
ASM File Details & Top Consumers
Check MOUNT_STATUS & HEADER_STATUS together
A disk can show MOUNTED but have a degraded HEADER_STATUS. Always check MOUNT_STATUS = CACHED and HEADER_STATUS = MEMBER for healthy disks
Monitor v$asm_operation during Maintenance
Rebalance can silently stall. Monitor v$asm_operation throughout any add/drop or resize operation to catch issues early.
Set Alerts at 80–85% usage
Don't wait until 100%. Configure monitoring alerts at 80% so your team has time to add capacity before it becomes a crisis.