Update 21-Sep-2011: It’s definitely was a bug in an early 11g release. As cp command does work in the latest release. Nevertheless, triple check the results if you are using it as part of your backup strategy. Don’t forget to test regularly!
Since the introduction of ASM in Oracle 10g Release 1, every ASM administrator has been dreaming of a simple command line tool to copy files between ASM diskgroups and other filesystems. Oracle ASM 10g Release 2 added the handy
asmcmd utility, but even though everyone expected a copy command there, it had not been implemented.
The only way to copy files to or from an ASM diskgroup was either to use RMAN, to configure XDB for FTP access, or use the
DBMS_FILE_TRANSFER package. No wonder that the
cp command is the most popular addition to
asmcmd tool in Oracle ASM 11g: the hardest barrier to convincing my customers to use ASM has been the inability to access the files and copy them to the OS filesystem using the command-line copy command. Customers wanted to “feel” the files and be able to easily manipulate them.
While working on a Collaborate 08 presentation on Oracle 11g new features out-of-the-box, I was verifying new commands in Oracle ASM 11g’s
asmcmd utility. It turned our that copying files from or to ASM is still a problem.
First, I tried to copy a single text file to an ASM diskgroup:
ASMCMD> cp /home/oracle/.bash_profile +dg2/test.file source /home/oracle/.bash_profile target +dg2/test.file ASMCMD-08012: can not determine file type for file->'/home/oracle/.bash_profile' ORA-15056: additional error message ORA-17503: ksfdopn:DGGetFileAttr15 Failed to open file /home/oracle/.bash_profile ORA-27046: file size is not a multiple of logical block size Additional information: 1 ORA-06512: at "SYS.X$DBMS_DISKGROUP", line 207 ORA-06512: at line 3 (DBD ERROR: OCIStmtExecute)
Hmm . . . Okay. Let’s try to do it in multiples of diskgroup blocks:
ASMCMD> lsdg State Type Rebal Sector
AU Total_MB... MOUNTED EXTERN N 512
1048576 2048... MOUNTED NORMAL N 512
2097152 200... ASMCMD> exit [oracle@lh8 ~]$ dd if=/dev/zero of=/home/oracle/test2.file bs=4k count=10 10+0 records in 10+0 records out [oracle@lh8 ~]$ asmcmd ASMCMD> cp /home/oracle/test2.file +DG2 source /home/oracle/test2.file target +DG2/test2.file ASMCMD-08012: can not determine file type for file->'/home/oracle/test2.file' ORA-15056: additional error message ORA-19762: invalid file type DGGetFileAttr20 ORA-06512: at "SYS.X$DBMS_DISKGROUP", line 207 ORA-06512: at line 3 (DBD ERROR: OCIStmtExecute)
Oops. It seems I can’t put any file to ASM. Not that I’m very surprised — I expected that ASM would “automagically” try to place all files based on OMF standards and templates. There are, however, only templates and rules for database files in 11g.
Right, let me try to backup a controlfile to a filesystem and copy it to ASM:
RMAN> backup format '/tmp/backup.ctl' current controlfile; ... channel ORA_DISK_1: finished piece 1 at 06-APR-08 piece handle=/tmp/backup.ctl tag=TAG20080406T202034 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03 ... ASMCMD> cp /tmp/backup.ctl +dg2/backup.ctl source /tmp/backup.ctl target +dg2/backup.ctl copying file(s)... file, +DG2/backup.ctl, copy committed. ASMCMD> ls -l +dg2/backup.ctl Type Redund Striped Time Sys Name N backup.ctl => +DG2/ASMTESTING/BACKUPSET/TESTING.256.651356493
Alright. That seems to work, except that ASM chose a bizarre location. For some reason, I’m not surprised again — I kind of expected it to place it somewhere into
DB_UNKNOWN like RMAN does when recovering
SPFILE from autobackup. In the best Oracle traditions of keeping things consistent,
ASMTESTING seems to be reasonable. Was it a hard-coded leftover from the test implementation of the
cp command? I wouldn’t be surprised, it’s deja-vu.
We can be patient and forgive this for the first release. Let’s try to copy it to a filesystem and back:
ASMCMD> cp +dg2/backup.ctl /tmp/backup.ctl2 source +dg2/backup.ctl target /tmp/backup.ctl2 copying file(s)... file, /tmp/backup.ctl2, copy committed. ASMCMD> cp /tmp/backup.ctl2 +dg2/backup.ctl2 source /tmp/backup.ctl2 target +dg2/backup.ctl2 ASMCMD-08012: can not determine file type for file->'/tmp/backup.ctl2' ORA-15056: additional error message ORA-19762: invalid file type DGGetFileAttr20 ORA-06512: at "SYS.X$DBMS_DISKGROUP", line 207 ORA-06512: at line 3 (DBD ERROR: OCIStmtExecute)
Now, that is odd. Perhaps I need to register this file with the database (i.e. in the controlfile)? Let’s ask RMAN to catalog this file:
[oracle@lh8 ~]$ ls -l /tmp/backup.ctl* -rw-r----- 1 oracle dba 9797632 Apr 6 20:20 /tmp/backup.ctl -rw-r----- 1 oracle dba 9797632 Apr 6 20:22 /tmp/backup.ctl2 ... RMAN> catalog start with '/tmp/backup.ctl2'; ... List of Files Which Where Not Cataloged ======================================= File Name: /tmp/backup.ctl2 RMAN-07517: Reason: The file header is corrupted
So the file got corrupted while copying from ASM to a filesystem? Okay. Let’s try an ASM -> ASM copy:
ASMCMD> cp +dg2/backup.ctl +dg2/backup.ctl3 source +dg2/backup.ctl target +dg2/backup.ctl3 copying file(s)... file, +DG2/backup.ctl3, copy committed. ... RMAN> catalog start with '+dg2'; ... List of Files Which Where Not Cataloged ======================================= File Name: +dg2/backup.ctl RMAN-07517: Reason: The file header is corrupted File Name: +dg2/backup.ctl3 RMAN-07517: Reason: The file header is corrupted
Hey, both files are actually corrupted, so the corruption occurred in the first copy, from the filesystem to ASM. Alright. Let’s try to simply copy a current controlfile within ASM:
ASMCMD> cp +dg1/db11g/controlfile/Current.256.651275203 +dg2/asm_copy source +dg1/db11g/controlfile/Current.256.651275203 target +dg2/asm_copy copying file(s)... file, +DG2/asm_copy, copy committed. ASMCMD> ls -l +dg2/asm_copy Type Redund Striped Time Sys Name N asm_copy => +DG2/ASMTESTING/CONTROLFILE/TESTING.258.651358725 ... RMAN> catalog start with '+dg2'; ... List of Files Which Where Not Cataloged ======================================= File Name: +dg2/asm_copy RMAN-07517: Reason: The file header is corrupted
These results are disappointing — I couldn’t make the
cp command work even a single time.
I should note that I did ask my old good friends, Metalink and Google, about ASMCMD-08012 and the like, but they came back empty.
If anyone has been able to test the ASMCMD
cp command in 11g, please share your experience.
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