The Oracle Zero Data Loss Recovery Appliance racks have a flexible configuration that allows a minimum of three storage servers, and can be extended based on version.

• RA23: a total of 17 storage servers. Usable capacity normal redundancy, 92 TB per storage server, or minimum (3 storage servers) 274 TB and full rack total 1,564 TB. The usable capacity under high redundancy is 60 TB per storage server.
• RA21: a total of 18 storage servers. Usable capacity normal redundancy 70 TB per storage server, or minimum (3 storage servers) 207 TB and full rack total 1,260 TB. The usable capacity under high redundancy is 44 TB per storage server.
• X8M, and X8 through X5: a total of 18 storage servers.
• X4: a total of 14 storage servers.

All Recovery Appliance racks have two compute servers, regardless of the number of storage servers.

This chapter describes how to expand a Recovery Appliance rack by adding storage servers. It contains the following sections:

• Preparing to Extend Recovery Appliance

• Precautions and Guidelines

• Adding Storage Servers to a Rack

• Making New Storage Available

• Preparing to Extend Recovery Appliance
  
• Precautions and Guidelines
  
• Adding Storage Servers to a Rack
  
• Making New Storage Available
  After you add storage servers to a rack to increase the storage capacity of an existing system, you must run racli commands to make the additional storage available for backups.