IBM 000-8697 Manual Do Utilizador

Operating OnLine

If the

LTAPEDEV

 and

TAPEDEV

 values are the same, you must plan your

logical log file backups to leave the maximum amount of free space available
before the archive begins. If the logical log files fill while the archive is under
way, normal OnLine processing stops. If this happens, your options are
limited. You can either abort the archive to free the tape device and back up
the logical logs or leave normal processing suspended until the archive
completes.

You might decide to set

LTAPEDEV

to /dev/null (and not keep logical log file

backups) under the following conditions:

■

If your environment does not include a tape device but you want to
use OnLine, set both

LTAPEDEV

 and

TAPEDEV

 (the archive tape

device) to /dev/null.

■

If you do not care about data recovery beyond the information that
is available from archives, set

LTAPEDEV

 to /dev/null. If data

recovery is irrelevant, set both

LTAPEDEV

and

TAPEDEV

to /dev/null.

When

LTAPEDEV

is set to /dev/null, OnLine does not wait for a backup before

marking the logical log files as backed up. Instead, as soon as a logical log file
becomes full, it is immediately marked as backed up (status B).

When the last open transaction in the log is closed, the log file is marked free
(status F). As a result, no logical log data is stored. This means that, in the
event of failure, you cannot restore work done since the most-recent archive.

Verify that the current block size and tape size are appropriate for the device
specified. The block size of the logical log tape device is specified as

LTAPEBLK

. The tape size is specified as

LTAPESIZE

.

If

LTAPEDEV

 is specified as /dev/null, block size and tape size are ignored.

Specify

LTAPEBLK

 as the largest block size permitted by your tape device.

Specify

LTAPESIZE

 as the maximum amount of data you can write to this

tape.