Expanding Storage Capacity in Oracle Database, Adding a Disk to Diskgroup Data1

Expanding Storage Capacity in Oracle Database, Adding a Disk to Diskgroup Data1

SQL Code

Note: Wildcards can be used for raw device names (eg. raw*

1alter diskgroup data1
2add disk '/dev/raw/raw4'

Sample Oracle Output:

2no rows selected

Description of the Oracle Database SQL code:


  • The primary purpose of this SQL code is to expand the storage capacity of an existing disk group named "data1" within an Oracle database environment.
  • It achieves this by adding a new physical disk, identified as '/dev/raw/raw4', to the existing disk group.


  • alter diskgroup: This keyword initiates the modification of a disk group within the database. It signals a change to its structure or configuration.
  • data1: This specifies the name of the target disk group that will undergo the modification.
  • add disk: This clause instructs the database to incorporate a new disk into the specified disk group.
  • '/dev/raw/raw4': This denotes the exact path or identifier of the physical disk that will be added to the disk group.
  • /: This symbol serves as the terminator for the SQL statement, indicating its completion.

Key Points:

  • Disk Groups: In Oracle databases, disk groups act as logical containers that manage a collection of physical disks. They offer performance benefits, redundancy, and simplified management of storage resources.
  • ASM (Automatic Storage Management): This Oracle feature often handles disk groups, providing automated management and optimization of storage.
  • Rebalancing: After adding a disk, Oracle typically rebalances the data distribution within the disk group to ensure optimal performance and even utilization of available storage.

Additional Insights and Explanations:

  • Capacity Expansion: Adding disks is a common strategy to accommodate growing data volumes, ensuring sufficient storage for database operations.
  • Performance Enhancement: Distributing data across multiple disks can improve performance by enabling parallel reads and writes, reducing I/O bottlenecks.
  • Redundancy: Disk groups can employ mirroring or other redundancy mechanisms to protect data from disk failures, enhancing data resilience.
  • Maintenance: Adding disks may necessitate database downtime or temporary performance impacts, depending on the specific configuration and rebalancing process.
  • Careful Planning: Thoroughly assess storage requirements and performance needs before making disk modifications to ensure optimal outcomes.

Posts in this series