Linux supports multiple tape device strategies and hardware. Backup Server supports only physical tape backup hardware which works per the “mtio” software layer interface.
This includes all generic SCSI-1/-2 tape hardware. Before configuring the backup devices within Adaptive Server you must understand and configure the system tape initialization properly.
Backup Server supports variable block and async tape storage. Log in as “root” to enable these at system start-up. A configuration file /etc/stinit.def should be in place and a command should be run to force the generic st(8) interface into the desired mode.
For any Backup Server configured tape unit set the below:
noblklimits=0 # Force variable block mode. can-bsr # The unit does handle back space records. async-writes=0 # Desired 0 - No async tape operations (adviced). async-writes=1 # Desired 1 - Async tape operations are enabled. two-fms=1 # Write two (2) end-of-file markers. buffering=0 # Disable buffering - must if async = 1.
This example configures a DDS-[1234] 4mm tape unit:
[/etc/stinit.def]
# A compressing DAT (DDS-1-DC or DDS-[234])
manufacturer=HP model = "C1533A" {
scsi2logical=1 can-bsr noblklimits=0 async-writes=0 two-fms=1 buffering=0 read-ahead=0
mode1 blocksize=0 compression=1
mode2 blocksize=1024 compression=1
mode3 blocksize=0 compression=0
mode4 blocksize=1024 compression=0
}
Tape units are first accessible per their entries under /dev. Rewind devices are required. The first unit presents itself as nst0; thenext as nst1,and so on.
You should understand device mappings as described within the man-page towards st(8)reference page.
By default, Adaptive Server configures two backup devices within sysdevices named:
logical device 'tapedump1' towards physical device '/dev/nst0'.
logical device 'tapedump2' towards physical device '/dev/nst1'.
