Protecting backup volumes

All backup volumes created during an FDDRL run (between the START-JOBS statement and the end of the job), are part of the same save run. They all receive the same date and time ID. A volume can only be used once during a save run, except in the case of a restart (see section "Restart" below) or if the volumes are used again for the same disk following an aborted run. A retention period can be issued for the volumes of a save run; the backup volumes must not be overwritten during this period. All backup volumes to which data is written are assigned the user-specified retention period in the HDR1 label. The retention period is specified as follows:

//MODIFY-FDDRL-PARAMETERS RETENTION-PERIOD=<integer 0..32767 days>

A backup volume can be protected against overwriting for up to 32767 days. Unless otherwise specified, the retention period is 0 days, but even then a backup volume cannot be overwritten during the same run.

The retention period is used to calculate the EXPIRATION-DATE. It is recorded in the MAREN catalog if MAREN is used.

WARNING! Risk of backup volumes being overwritten. A retention period of 1 day may not be sufficient for FDDRL runs taking place shortly before midnight, since the time of day is not taken into account when the expiration date is calculated.

Restart

If an unrecoverable write error is discovered while writing or reading on MTC, FDDRL issues a message inquiring whether a restart should be performed. If a restart is desired, FDDRL goes to the beginning of the aborted volume and writes the same data again.

If the MTC device caused the error, the same volume can be remounted onto another MTC device and written again. (This is the only case in which a tapeMTC can be written twice in the same save run.)

If the volume itself was the error source, another volume should be mounted. If the VSN was specified via the TAPE operand, the new volume must have the same VSN as the defective one.