Oracle-RMAN backup (2)

Oracle-RMAN backup (2) in Oracle RMAN backup (1), the backup of various files in RMAN is described. backup sets are replicated in RMAN backups. You can back up your own backups. That is, you can back up a file in multiple directories. oralce supports up to four backups. 1. The number of backups is available by default. configure datafile backup copies for device type disk to 1; # default can be used TO modify the default value TO meet the required requirements. 2. run the following command to create two folders b1 and b2 in the/u01 directory, backup copies 2 datafile 6 format = '/u01/b1/d _ % U','/u01/b2/d _ % U '; find this file in the b1 and b2 folders, [oracle @ oracle11g b1] $ lltotal 20452-rw-r ----- 1 oracle oinstall 20914176 Aug 24 [oracle @ oracle11g b2] $ lltotal 20452-rw-r ----- 1 oracle oinstall 20914176 Aug 24 d_20oi2abg_12. the image copy of the image backup file is exactly the same as that of the data file, control file, or archive log file. The result is as if the file is copied by the operating system, but the mechanism is different: RMAN reads and writes the oracle block instead of the operating system block. An image copy can be composed of data files, control files, and archive log files. It cannot be composed of spfiles. The backup command is as follows: RMAN> copy datafile 11 to '/u01/backup/paul02.dbf' tag = 'pol '; alternatively, RMAN> backup as copy datafile 11 format = '/u01/backup/paul22.dbf' tag = 'Paul'; for backing up the entire database, backup as copy database; backup the archive log file backup as copy archivelog all delete all input; by default, the configure channel device type disk format address is not specified (show all under RMAN ), the default address is flash_recovery_area. Iii. Parallel backup the use of parallel backup can shorten the backup time. Each channel can read one or more files and write one or more files. The degree of parallelism that can be achieved is limited by three factors: 1. Number of channels 2. Number of backup sets 3. Number of input files parallelism cannot exceed the number of input files-unless the multipart backup function is enabled. Command: RMAN> run2> {allocate channel t1 type disk; 3> allocate channel t2 type disk; 4> allocate channel t3 type disk; 5> backup database filesperset = 4 ;} the command is successfully executed when you run the following command. Isn't the degree of parallelism cannot exceed the number of input files? Why? RMAN> run {2> allocate channel t1 type disk; 3> allocate channel t2 type disk; 4> allocate channel t3 type disk; 5> backup database filesperset = 2 ;} or multiple files are backed up through the specified channel, where t3 is idle; RMAN> run {2> allocate channel t1 type disk; 3> allocate channel t2 type disk; 4> allocate channel t3 type disk; 5> backup format = '/u01/backup/cd _ % U' datafile 11 channel t2 6> datafile 6 channel t1;} When the file is several gigabytes or hundreds of megabytes, this backup file will need to be parallelized, usually one Only one file can be read through multiple channels. You can use the multipart backup function. RMAN> run {2> allocate channel t1 type disk; 3> allocate channel t2 type disk; 4> allocate channel t3 type disk; 5> backup datafile 11 section size 3 m; 6>}