IBM 000-8697 Manual Do Utilizador

IBM Informix OnLine Database Server Administrator’s Guide

Mirroring activity does not begin until you define mirror chunks for a
dbspace or a blobspace and explicitly start mirroring. Do not enable
mirroring until you are ready to define the mirror chunks.

Mirroring is enabled when the value of the

MIRROR

 shared-memory config-

uration parameter is set to 1.

You can change the value of

MIRROR

 while OnLine is in online mode but it

will not take effect until you reinitialize shared memory (take OnLine offline
and then to quiescent or online mode).

If you are logged in as user informix, you can make this change from within

DB-M

onitor or from the command line. If you are logged in as root, you must

use the command-line option.

If you make the change from within

DB-M

onitor, you risk inadvertently reini-

tializing OnLine and destroying all data. This risk is present because you
access the

MIRROR

parameter through the Initialize option of the Parameters

menu.

From within

DB-M

onitor, select the Parameters menu, Initialize

option to enable mirroring. In the field labelled

Mirror

, enter a

Y

.

Press

ESC

 to record changes.

When the screen of shared-memory parameters appears, press

ESC

to

save the rest of your configuration without changes.

When the prompt appears to confirm that you want to save the
changes to your configuration, respond

Y

 (yes).

When a second prompt appears to confirm that you want to continue
(to initialize OnLine disk space and destroy all existing data),
respond

N

 (no).

Reinitialize shared memory (take OnLine offline and then to
quiescent mode) for the change to take effect.