IBM 000-8697 User Manual

IBM Informix OnLine Database Server Administrator’s Guide

OnLine supports a logical log backup option called Continuous-Logging,
which backs up each logical log as soon as it becomes full. The Continuous-
Logging option is recommended for all OnLine configurations, but it requires
a dedicated tape device while the option is active.

Informix strongly recommends that your OnLine environment include two
tape devices, one for continuous backup of the logical logs and one for
archiving.

LTAPEDEV

 specifies the logical log backup tape device.

LTAPEDEV

 can be a

link pathname that points to the actual tape device to provide flexibility in
case the actual device is unavailable.

The default value of

LTAPEDEV

 is /dev/tapedev.

You can set the value of

LTAPEDEV

 to /dev/null if you are testing an appli-

cation or if you are using OnLine in a learning environment. The only
advantage of doing this is to eliminate the need for a tape device. However,
you cannot recover OnLine data beyond that which is stored as part of an
archive.

You can set the value of

LTAPEDEV

 to specify a tape device on another host

machine and perform logical log backups across your network. For instruc-
tions on how to do this, refer to

Tape devices that do not rewind automatically before opening and on closing
are considered incompatible with OnLine operation.

LTAPEBLK

 specifies the block size of the logical log backup tape device, in

kilobytes. Specify the largest block size permitted by your tape device. If the
pathname of the tape device is /dev/null, the block size is ignored. The
default value of

LTAPEBLK

 is 16

KB

.