Restore archivelogs to disk from ASM

During recovering a database, usually Oracle tells which archivelog is needed by specifying the sequence number, such as:
ORA-00279: change 39138275307 generated at 01/02/2009 00:12:07 needed for thread 1
ORA-00280: change 39138275307 for thread 1 is in sequence #78240

Here are the steps to get the necessary logs from the tape or from the ASM:

1. Make sure the status of archivelog is "AVAILABLE" on the tape, and the tape is also available on the tape drive.

RMAN> list backup of archivelog sequence 78240 thread 1;

2. Restore the archivelogs from the tape to the disk. But it may say the logs are already on the disk.

RMAN> run {
2> set archivelog destination to '/images';
3> ALLOCATE CHANNEL ch00 TYPE 'SBT_TAPE';
4> ALLOCATE CHANNEL ch01 TYPE 'SBT_TAPE';
5> restore archivelog from logseq=78240 until logseq=78241;
6> RELEASE CHANNEL ch00;
7> RELEASE CHANNEL ch01;
8> }

executing command: SET ARCHIVELOG DESTINATION

allocated channel: ch00
channel ch00: sid=1017 instance=pdw1 devtype=SBT_TAPE
channel ch00: Veritas NetBackup for Oracle - Release 6.5 (2007072323)

allocated channel: ch01
channel ch01: sid=1003 instance=pdw1 devtype=SBT_TAPE
channel ch01: Veritas NetBackup for Oracle - Release 6.5 (2007072323)

Starting restore at 12-JAN-09:06:50:05

archive log thread 1 sequence 78240 is already on disk as file +PFRA/pdb/archivelog/2009_01_02/thread_1_seq_78240.11985.675049215
archive log thread 1 sequence 78241 is already on disk as file +PFRA/pdb/archivelog/2009_01_02/thread_1_seq_78241.14012.675049273
restore not done; all files readonly, offline, or already restored
Finished restore at 12-JAN-09:06:50:06

released channel: ch00
released channel: ch01

3. Use RMAN "COPY" command to copy the logs from ASM to disk. Make sure the disk folder is writable.

RMAN> connect target
connected to target database: PDB (DBID=1190101294)

RMAN> copy archivelog '+PFRA/pdb/archivelog/2009_01_02/thread_1_seq_78240.11985.675049215' to '/images/archive_78240.arc';

Starting backup at 12-JAN-09:06:57:26
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=973 instance=pdb1 devtype=DISK
channel ORA_DISK_1: starting archive copy
input archive log thread=1 sequence=78240 recid=3055 stamp=675049214
output filename=/images/archive_78240.arc recid=3088 stamp=675932248
channel ORA_DISK_1: archivelog copy complete, elapsed time: 00:00:02
Finished backup at 12-JAN-09:06:57:29

Starting Control File and SPFILE Autobackup at 12-JAN-09:06:57:29
piece handle=+PFRA/pdb/autobackup/2009_01_12/s_675932297.12505.675932301 comment=NONE
Finished Control File and SPFILE Autobackup at 12-JAN-09:06:58:25

RMAN> copy archivelog '+PFRA/pdb/archivelog/2009_01_02/thread_1_seq_78241.14012.675049273' to '/images/archive_78241.arc';

Starting backup at 12-JAN-09:06:59:28
using channel ORA_DISK_1
channel ORA_DISK_1: starting archive copy
input archive log thread=1 sequence=78241 recid=3056 stamp=675049272
output filename=/images/archive_78241.arc recid=3089 stamp=675932369
channel ORA_DISK_1: archivelog copy complete, elapsed time: 00:00:02
Finished backup at 12-JAN-09:06:59:30

Starting Control File and SPFILE Autobackup at 12-JAN-09:06:59:30
piece handle=+PFRA/pdb/autobackup/2009_01_12/s_675932372.12504.675932373 comment=NONE
Finished Control File and SPFILE Autobackup at 12-JAN-09:06:59:34

RMAN> exit

That also shows a good way to copy files out from ASM.