You can modify the capacity of your Oracle Exadata using elastic configuration.

• Adding Storage Servers using OEDACLI
  OEDACLI automates elastic storage expansion on Oracle Exadata.
• Manually Adding a Storage Server
  This topic describes the step-by-step procedure to manually add a new storage server (or cell) to an existing Oracle Exadata elastic configuration.
• Adding a New Storage Server to an Eighth Rack Cluster
  Perform the following steps to add a new Oracle Exadata X7 or later storage server to an existing Oracle Exadata X7 or later Eighth Rack.
• Expanding an Existing Exadata Storage Grid
  
• Dropping a Storage Server from an Existing Disk Group or Storage Grid
  You can remove a storage server from an existing Oracle Exadata Rack.
• Dropping Storage Servers using OEDACLI
  OEDACLI provides the interface to drop storage servers for different configuration such as Bare Metal, single Oracle VM or multiple Oracle VMs.