STORE and TurboSTORE/iX Products Manual (B5151-90003)

38 Chapter3
Preparing Storage Devices
Preparation Process
Assigning Device File Names
When using multiple backup devices, you have the choice of entering multiple FILE
commands to assign a different filename to each device or a single FILE command.
Assigning each device a different filename makes it easier to keep track of each device's
position in the backup media. When you receive media requests, you know exactly to which
device the request applies. You may use LDEV numbers or a common device class in the
FILE command. When you use a device class to name backup devices, STORE asks you to
assign a logical device to the filename with a media request. Refer to Chapter 8, "Handling
Media Requests" for more information. You must use LDEV numbers to name devices if
the devices are to be automatically allocated.
Assign unique filenames based on each device's position in the backup. For example, if you
plan to use four parallel devices, you might issue the following set of FILE commands:
:FILE BACKA;DEV=7
:FILE BACKB;DEV=8
:FILE BACKC;DEV=9
:FILE BACKD;DEV=11
Label sequential devices in order. For example, if you are using three sequential devices,
you might issue the following FILE commands:
:FILE BACK1;DEV=TAPE
:FILE BACK2;DEV=TAPE
:FILE BACK3;DEV=TAPE
Label parallel device pools both in parallel and sequential order. For example:
:FILE BACKA1;DEV=7
:FILE BACKA2;DEV=8
:FILE BACKB1;DEV=9
:FILE BACKB2;DEV=11
If you issue a single FILE command when using multiple backup devices, you assign a
common filename and common device class to all of your backup devices. For example:
:FILE T;DEV=TAPE
You use the common filename, T in the example above, to refer to each device in your STORE
command. In a media request, the system asks you to assign an LDEV number to T for
each device. If you have four backup devices, you see four identical media requests. You
assign a different LDEV number to each media request based upon the order in which you
receive the requests. Refer to Chapter 8, "Handling Media Requests," for more
information.
Your FILE command gives the backup device a filename and identifies the device. To store
files to only one device, you backreference that device in your STORE command, as
described previously. For example:
:FILE T;DEV=TAPE
:STORE @.OPERATOR.SYS;*T