Chapter 6: Backup and Recovery

Overview

As with all computer systems, your work on the i5 should be backed up periodically so that you can recover lost data. Losing data is disastrous if you don't have a backup of everything you could possibly lose. It is better to be safe than sorry. Data can be lost for any of the following reasons:

• Someone accidentally deletes an item such as a file, a program, or a library.

• Someone intentionally and maliciously deletes an item. Pressing charges for sabotage and suing the person will not bring back the missing item.

• The mass update program you created did not work as expected, so your database is mangled.

• The new Accounting clerk selected the wrong menu option, ignored all the warning panels with bells and whistles you designed to make the clerk stop, and closed the fiscal year instead of the current month. The clerk will be fired for gross negligence, but you still have to restore the general ledger.

• One of your disk drives went down, and you will have to replace it. The manufacturer's warranty will get you a free replacement, but everything the old drive contained is irretrievable.

Initializing

You need to prepare the tape or diskette before you back up anything to tape or diskette. This process is called initialization.

Initializing Tapes

To initialize a tape, run the Initialize Tape (INZTAP) command. Here is an example:

INZTAP DEV(TAP01) NEWVOL(BACKUP) NEWOWNID(ABC_CORP) +


VOL(*MOUNTED) CHECK(*NO) DENSITY(*DEVTYPE) +


CODE(*EBCDIC) ENDOPT(*REWIND) CLEAR(*NO)

• DEV(TAP01) indicates that the tape to be initialized has been mounted on tape device TAP01. You must make sure that the tape drive is online and that the tape is not write-protected.

• NEWVOL(BACKUP) gives the tape a new volume ID of backup. Volume IDs can have a maximum of six characters .

• NEWOWNID(ABC_CORP) provides an owner name for this tape (such as your company name ).

• VOL(*MOUNTED) means that the INZTAP will initialize any tape that happens to be mounted on the drive, regardless of its current volume ID. For example, if you specify VOL(XYZ), the tape would be initialized only if it already had a volume ID of XYZ.

• CHECK(*NO) indicates that the system is not to check for active files on the tape. If the tape contains data, the data is ignored and the initialization continues. You can leave the default value of *YES if you would rather be warned that the tape contains data.

• DENSITY(*DEVTYPE) indicates that the tape should be initialized to whatever density is supported by the tape drive. Sometimes you can force other values, indicated in bits per inch (bpi), such as 1,600, 3,200, or as high as 43,200.

• CODE(*EBCDIC) means that the tape is initialized for EBCDIC backups . You can use the value *ASCII if you will be using that tape to restore on another system that supports ASCII.

• ENDOPT(*REWIND) indicates that the tape should be rewound after the initialization is complete. You also can indicate *UNLOAD, in which case the tape is rewound and unloaded.

• CLEAR(*NO) states that the tape drive is not to delete the tape of its current contents, which saves time. You also can specify *YES if you want the tape drive to erase the tape for you, but the tape will have to go all the way to the end and back.