The Oracle Database Appliance 2.4 Patch was released last week and provides you an option of ASM normal redundancy (double mirroring) during the initial deployment of the Database Appliance. The default deployment of the Oracle Database Appliance is high redundancy for the +DATA and +RECO disk groups. While there is 12TB of raw shared storage available, the Database Backup Location and Disk Group Redundancy govern how much usable storage is presented after the initial deployment is completed.

The Database Backup Location options are Local or External. When the Local Backup Option is selected, this means that 60% of the available shared storage will be allocated for the Fast Recovery Area that contains database backups and archive logs. The External Backup Option will allocate 20% of the available shared storage to the Fast Recovery Area.

So, let’s look at an example of High Redundancy and External Backups.

• Disk Group Redundancy – High --> Triple Mirroring to provide ~4TB of available storage
• Database Backup Location – External --> 20% of available shared storage allocated to +RECO
• +DATA = 3.2TB of usable storage, +RECO = 0.8TB of usable storage

What about Normal Redundancy with External Backups?

• Disk Group Redundancy – Normal --> Double Mirroring to provide ~6TB of available storage
• Database Backup Location – External --> 20% of available shared storage allocated to +RECO
• +DATA = 4.8TB of usable storage, +RECO = 1.2TB of usable storage

As a best practice, we would recommend using Normal Redundancy for your test and/or development Oracle Database Appliances and High Redundancy for production.