Oracle ASM Diskgroup Usage Report

Overview

This repository contains a shell script that generates a usage report for Oracle ASM diskgroups, with a special focus on FRA / recovery diskgroups (for example +RECO, +FRA). The report shows total space, used space, free space and usage percentage, helping DBAs monitor capacity and plan growth in Exadata, ExaCC and on-prem environments.

The script is designed to be simple, portable and easy to integrate with cron, monitoring tools or email notifications.

Features

• Collects ASM diskgroup usage information from V$ASM_DISKGROUP
• Shows, for each diskgroup:
  • Name
  • Total size (GB)
  • Used size (GB)
  • Free size (GB)
  • Usage percentage
• Can optionally filter only FRA / recovery diskgroups (by name pattern)
• Output is plain text / pipe-separated, easy to parse with other tools
• Suitable for scheduled execution via cron
• Safe to run in production environments (read-only views)

Example query used

The core logic of the script is based on a query similar to:

SELECT name,
       total_mb,
       free_mb,
       (total_mb - free_mb) AS used_mb,
       ROUND( (total_mb - free_mb) / total_mb * 100, 2 ) AS pct_used
  FROM v$asm_diskgroup
 ORDER BY name;

Requirements

• Linux environment
• Bash
• SQL*Plus client installed
• Oracle Grid / ASM environment configured (ORACLE_HOME for Grid, ORACLE_SID for ASM instance)
• User with access to V$ASM_DISKGROUP (typically sysasm or OS authentication as grid/asm owner)

Usage

1. Clone the repository:

   git clone https://github.com/guborges/oracle-asm-diskgroup-usage-report.git
   cd oracle-asm-diskgroup-usage-report
   

2. Edit the script configuration:

   • Set how you connect to ASM:
     • OS authentication (for example, running as grid user with sqlplus / as sysasm)
     • Or a connect string if you prefer
   • Optionally set a name pattern to focus on FRA / recovery diskgroups (for example +RECO%)

3. Make the script executable:

   chmod +x asm_diskgroup_usage.sh
   

4. Run the script:

   ./asm_diskgroup_usage.sh
   # or, with an explicit connect string:
   ./asm_diskgroup_usage.sh "+asm_user/password@+ASM as sysasm"
   

5. Example output:

   DISKGROUP|TOTAL_GB|USED_GB|FREE_GB|PCT_USED
   DATA   | 914.00 | 580.15| 333.85| 63.49
   RECO   | 228.00 |  25.88| 202.12| 11.35
   

This output can be sent by email, ingested by monitoring tools or stored for capacity trending.

File structure

oracle-asm-diskgroup-usage-report/
├── asm_diskgroup_usage.sh
└── README.md

Notes

• The script is intentionally minimal to keep it easy to read and adapt.
• You can extend it to:
  • Highlight diskgroups above a certain usage threshold (for example 80% or 90%)
  • Generate HTML or CSV reports
  • Send alerts by email or webhook when usage exceeds a limit
  • Store historical data in a table or file for trending

The approach works well in Exadata / ExaCC environments where FRA growth in ASM diskgroups must be monitored closely to avoid backup and archive log issues.

License

MIT License