Backup methods
The following two backup methods are supported:
Combining backup to tape media with high-speed backup to disk
High-speed backup to disk is a function for implementing high-speed backup between volumes, regardless of volume capacities, using the Advanced Copy Function (OPC/EC) of ETERNUS disk storage systems. Backup to tape media is performed from the backup destination disk. Therefore, this function can greatly reduce the time during which system service is stopped for backup. Using EC enables faster backup because it supports differential copying for updates.
This backup method requires a backup destination disk.
The figure below shows the operation for backup to tape media via disk.
Figure 1.7 Combining backup to tape media with high-speed backup to disk
Backup method directly to tape
This method performs backup to tape media directly from a transaction volume without using the Advanced Copy Function of the ETERNUS disk storage systems. Transactions cannot be restarted until tape backup is completed. Therefore, it increases the time during which transaction must be stopped for backup.
The figure below shows the operation for backup to tape.
Figure 1.8 Method for direct backup to tape
Restoration methods
The following two restoration methods are supported:
Restoration from disk
When backup data is stored on a disk, the Advanced Copy Function (OPC/EC) of ETERNUS disk storage systems is used for restoration. This method can implement restoration instantaneously regardless of the size of a transaction volume.
Restoration from tape media
When backup data is stored on tape, data is directly written to a transaction volume from tape media. This increases the time required for restoration.
Coordination with the transaction server
When the transaction server is active
Backup data is guaranteed by coordination between the Tape Server and the transaction server.
When the transaction server is inactive
Restoration from the tape server independent of transaction is possible. This function can be used to recover system volumes.
Backup history management
Centralized management of backup to both disk and tape media
Backup data of transaction volumes is centrally managed as history information regardless of the backup destination media. Automatic management is also possible by setting the number of preservation generations or preservation days.
Operation managed by the number of preservation generations is referred to as "generation management backup", and operation managed by the number of preservation days is referred to as "day management backup".
In generation management backup mode, backup data is assigned a unique number called a generation number. An absolute generation is assigned uniquely to each transaction volume regardless of the media type (disk or tape). A relative generation is assigned uniquely to respective data stored on the disk or tape media.
Progress check for operation
The progress of backup, restoration, or tape copy being executed, or the result of the execution, can be checked.
