Database Reference
In-Depth Information
Sometimes, you may want to limit the overall size of a backup piece because of physical limitations of storage
devices. Use the
MAXPIECESIZE
parameter of the
CONFIGURE CHANNEL
or
ALLOCATE CHANNEL
command do this; for
example,
RMAN> configure channel device type disk maxpiecesize = 2g;
If you need to set the maximum number of bytes that RMAN reads each second on a channel, you can do so,
using the
RATE
parameter. This configures the maximum read rate for channel 1 to 200MB per second:
configure channel 1 device type disk rate 200M;
If you have a limit on the number of files you can have open simultaneously, you can specify a maximum open
files number via the
MAXOPENFILES
parameter:
RMAN> configure channel 1 device type disk maxopenfiles 32;
You may need to configure any of these settings when you need to make RMAN aware of some OS or hardware
limitation. You'll rarely need to use these parameters but should know of them.
23. Configuring Informational Output
A good practice is to always set the OS
NLS_DATE_FORMAT
variable (before running RMAN) so that both the date and
time information are displayed in the RMAN log instead of just the date, which is the default:
export NLS_DATE_FORMAT='dd-mon-yyyy hh24:mi:ss'
This is useful during troubleshooting, especially when RMAN fails, because we can use the exact date/time
information for when the RMAN error occurred and compare it with the
alert.log
and OS/MML logs to verify what
other events occurred in the database/server.
Also consider executing
SET ECHO ON
to ensure that RMAN commands are displayed within the log before the
command is executed. Execute
SHOW ALL
as well to display the current settings of RMAN variables. These settings are
useful when troubleshooting and tuning.
CLearING aLL rMaN CONFIGUratIONS
there is no
CLEAR ALL
command for resetting all rMan configurations back to the default values. however, you
can easily simulate this by running a script that contains
CONFIGURE...CLEAR
commands:
CONFIGURE RETENTION POLICY clear;
CONFIGURE BACKUP OPTIMIZATION clear;
CONFIGURE DEFAULT DEVICE TYPE clear;
CONFIGURE CONTROLFILE AUTOBACKUP clear;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK clear;
CONFIGURE DEVICE TYPE DISK clear;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK clear;
CONFIGURE CHANNEL 1 DEVICE TYPE DISK clear;
CONFIGURE CHANNEL 2 DEVICE TYPE DISK clear;
CONFIGURE CHANNEL 3 DEVICE TYPE DISK clear;
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK clear;
