Mount / Dismount Command (SAP Library - Database Administration (Oracle) with SAPDBA)

Mount / Dismount Command

Before accessing a tape or several tapes for the first time the mount command defined in parameter mount_cmd is called up so that the automatic mounting of the tape or tapes can be carried out.
When the backup has been completed the corresponding tape devices are transferred from BRBACKUP/BRARCHIVE into the offline modus (EJECT). After this the dismount command defined in the parameter dismount_cmd is called up to dismount the tapes.

For some devices (e.g. HP 48AL) the tapes may not be transferred into offline mode. The dismount command is then sufficient for the dismounting of the tapes. The init<SID>.sap parameter rewind_offline should be marked off in these cases.

The mount and dismount commands use special control drivers which are defined in the parameter tape_address_ctl or tape_address_ctl_arch.

Syntax of the commands mount/dismount:

mount_cmd = "<mount_cmd> $ $ $ [$ ]"
dismount_cmd = " <dismount_cmd> $ $ [$ ]"

There are four position options for the mount command and three for the dismount command, represented by the $ character. The last option can be left out, depending on the implementation.

Meaning of the options $:

The first option identifies the database to be backed up and has the following structure:

<DBSID>-A for BRARCHIVE and BRRESTORE with option -a|-a1|-a2,

<DBSID>-B for BRBACKUP and BRRESTORE without option -a|-a1|-a2.

<DBSID> : ORACLE system ID (database instance)

This option can be used for the identification of a subset of tapes ("subpool") for the database to be backed up. The additional extension "-A" and "-B" enables separate subpools for BRARCHIVE- and BRBACKUP tapes to be defined and administrated.

The second option identifies the tape devices, on which the mount or dismount operations are to be carried out, through the control driver addresses:

<dev_addr1>[,<dev_addr2>,... ]

<dev_addr> : Driver address of the tape unit

One or more of the tape devices defined in the parameter tape_address_ctl can be spoken to.

Only for the parameter mount_cmd: The third option defines the tape names which are to be mounted on the tape devices stated in the second option:

< tape name1>[,<tape name2>,... ]|SCRATCH

<tape name> : Name of the tape to be mounted

The tape names are chosen from the data carrier list volume_backup (from BRBACKUP) or volume_archive (from BRARCHIVE) by the automatic tape administrator. The assignment of the tapes on the tape devices can be defined freely by the mount command. The number of tape names can be bigger than the number of driver addresses. In this case any number of tapes from this list can be mounted on the given tape devices.
The reserved tape name SCRATCH means that any unlocked tapes (in the sense of the BRBACKUP/BRARCHIVE waiting period) can be mounted. Which of the available tapes is mounted is decided by the mount command.

The last option (the fourth for mount_cmd, the third for dismount_cmd) transfers the name of a parameter file to the mount or dismount command, which contains additional configuration parameters for these commands. The name of the file is defined in the init<DBSID>.sap parameter mount_par_file or by the command option -r|-parfile.

The user must provide the mount or dismount command in the form of a program, shell script or a batch file.

The successful completion of the command is indicated by the exit code 0 and the absence of any output.