Databases Reference
In-Depth Information
You can also use the
validate
command to check all data files at once, as shown here:
RMAN> validate database;
Starting validate at 28-SEP-12
using channel ORA_DISK_1
channel ORA_DISK_1: starting validation of datafile
channel ORA_DISK_1: specifying datafile(s) for validation
input datafile file number=00004 name=/u01/app/oracle/oradata/catdb/cattbs_01.dbf
...
File Status Marked Corrupt Empty Blocks Blocks Examined High SCN
---- ------ -------------- ------------ --------------- ----------
5 OK 0 12673 12800 498714
File Name: /u01/app/oracle/oradata/catdb/virt_catalog1.dbf
Block Type Blocks Failing Blocks Processed
---------- -------------- ----------------
Data 0 0
Index 0 0
Other 0 127
...
Control File OK 0 494
Finished validate at 28-SEP-12
RMAN>
Note that when you issue the backup
... validate
command, the command begins with the message “Starting
validate” and not “Starting backup,” as is the case with the
backup ... validate
command.
How It Works
The semantics of the
validate
command are similar to those of the
backup ... validate
command, with the big
advantage that the
validate
command can check at a much more granular level than the
backup ... validate
command. You can use the
validate
command with individual data files, backup sets, and even data blocks.
■
Note
the
validate
command checks only for intrablock corruption, which may be either physical or logical
in nature.
You can speed up the validation of a large data file by using the
section size
clause with the
validate
command after first configuring multiple channels. The allocation of multiple channels with the
section size
clause
parallelizes the data file validation, making it considerably faster. Here's an example using two disk channels, with the
section size
clause dividing up the validation work between the two channels:
RMAN> run {
2> allocate channel ch1 device type disk;
3> allocate channel ch2 device type disk;
4> validate datafile 1 section size = 250m;
5> }
