Creating Logical Device Names for Local Dump Devices

If you are dumping to or loading from local devices (that is, if you are not performing backups over a network to a remote Backup Server), you can specify dump devices either by providing their physical locations or by specifying their logical device names.

In the latter case, you may want to create logical dump device names in the sysdevices system table of the master database.

Note: If you are dumping to or loading from a remote Backup Server, you must specify the absolute path name of the dump device. You cannot use a logical device name.

The sysdevices table stores information about each database and backup device, including its physical_name (the actual operating system device or file name) and its device_name (or logical name, known only within SAP ASE). On most platforms, SAP ASE has one or two aliases for tape devices installed in sysdevices. The physical names for these devices are common disk drive names for the platform; the logical names are tapedump1 and tapedump2.

When you create backup scripts and threshold procedures, use logical names, rather than physical device names, and whenever possible, modify scripts and procedures that refer to actual device names each time you replace a backup device. If you use logical device names, you can simply drop the sysdevices entry for the failed device and create a new entry that associates the logical name with a different physical device.

Note: Make sure that the device driver options you include with the dump command are accurate. Backup Server does not verify any device driver options you include during a dump command. For example, if you include a option that forces Backup Server to rewind a tape before use, it always rewinds the tape to the beginning instead of reading the tape from the point of the dump.

To list the backup devices for your system, run:
select * from master..sysdevices 
  where status = 16 or status = 24 
To list both the physical and logical names for database and backup devices, use sp_helpdevice:
sp_helpdevice tapedump1
device_name physical_name
 status cntrltype vdevno vpn_low      vpn_high
 ------ --------- ------------- -------- -------
tapedump1 /dev/nrmt4
tape, 625 MB, dump device
     16         3              0        0   20000