Determining the Size of a Backup or Export

Every database backup and export stored in a repository requires file system space (in megabytes) that is equivalent to the value assigned to the PermSize attribute plus the sum of file sizes of the transaction log files created after the latest checkpoint, per replica set.

The file size of transaction log files and how many are typically written between background checkpoints is dependent of the configuration of your database. Your typical workload and the settings of attributes like CkptFrequency, CkptLogVolume, and LogFileSize have direct impact in determining how many transaction log files would need to be considered for a backup or export operation. See Storage Provisioning for Transaction Log Files in Oracle TimesTen In-Memory Database Operations Guide.

Additionally, each data instance requires available temporary file system space (/instance_home/grid/admin/temp/) that is equivalent to the size of a database backup or database export divided by the number of replica sets for every normal backup, export, restore, or import operation. Staged backups only require temporary file system space equivalent to one transaction log file (LogFileSize).