ASM datafile operation in NOMOUNT

Hi

Several times I have been asked to manipulate with data files placed on ASM. In 11g there is a very nice feature – Oracle added a cp command to asmcmd tool but in 10g we have to use database instance to do all work.
One of very common task is coping a data file from one ASM disk group to other one. It can be done via RMAN copy command but this command adds an entry to RMAN repository. There is another method to do that and I found it in Oracle documentation (Yes, yes, RTFM). Convert command can be used not only to copy data file from ASM to file system and vice versa but to copy between ASM groups too.

Example

RMAN> convert datafile '+DATA/PIORO/DATAFILE/ORABPEL.260.692892311' format '+DATA/PIORO/copyofORABPEL';
Starting backup at 10-AUG-09
using channel ORA_DISK_1
channel ORA_DISK_1: starting datafile conversion
input filename=+DATA/pioro/datafile/orabpel.260.692892311
converted datafile=+DATA/pioro/ copyofORABPEL
channel ORA_DISK_1: datafile conversion complete, elapsed time: 00:00:25
Finished backup at 10-AUG-09

ASM to file system

RMAN> convert datafile '+DATA/PIORO/DATAFILE/ORABPEL.260.692892311' format '/home/oracle/copyofORABPEL';
Starting backup at 10-AUG-09
using channel ORA_DISK_1
channel ORA_DISK_1: starting datafile conversion
input filename=+DATA/pioro/datafile/orabpel.260.692892311
converted datafile=/home/oracle/copyofORABPEL
channel ORA_DISK_1: datafile conversion complete, elapsed time: 00:00:26
Finished backup at 10-AUG-09

Keep in mind that this command doesn’t add any information to control file so you want to rename a file you have to maintain it manually.

This command is working in NOMOUNT state too but a additional parameter is required

[oracle@piorovm ~]$ rman target /
Recovery Manager: Release 10.2.0.4.0 - Production on Mon Aug 10 22:15:44 2009
Copyright (c) 1982, 2007, Oracle.  All rights reserved.
connected to target database: pioro10 (not mounted)

RMAN> convert datafile '+DATA/PIORO/DATAFILE/ORABPEL.260.692892311' from platform 'Linux IA (32-bit)' format '/home/oracle/copyofORABPEL';
Starting backup at 10-AUG-09
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=154 devtype=DISK
channel ORA_DISK_1: starting datafile conversion
input filename=+DATA/pioro/datafile/orabpel.260.692892311
converted datafile=/home/oracle/copyofORABPEL
channel ORA_DISK_1: datafile conversion complete, elapsed time: 00:00:26
Finished backup at 10-AUG-09

If you need to copy archive log (ex. From flash recovery area) you can use a RMAN copy command - this is running only in MOUNT state.

RMAN> copy archivelog '+data/PIORO/ARCHIVELOG/2009_07_28/thread_1_seq_58.266.693419455' to '/home/oracle/arch_1_58';
Starting backup at 10-AUG-09
using channel ORA_DISK_1
channel ORA_DISK_1: starting archive copy
input archive log thread=1 sequence=58 recid=1 stamp=694559795
output filename=/home/oracle/ arch_1_58 recid=3 stamp=694560324
channel ORA_DISK_1: archivelog copy complete, elapsed time: 00:00:07
Finished backup at 10-AUG-09

But it can be a dangerous command because additional entry to control file is created and if you delete this file from a file system without sending that information to RMAN archive log backup could failed. To avoid it always CROSSCHECK ARCHIVELOG ALL before archive log backup or use option “skip inaccessible”.
This is it for today but I have some additional ideas to check.


Marcin