How to Copy Files in ASM

cp command in ASMCMD actually not copies system generated the file but creates an alias for real file. Here is a procedure to copy system generated file (redo log) from one asm datagroup to an other:

1-) Login a database which has access to asm disk groups

2-) Create following directories

CREATE OR REPLACE DIRECTORY SOURCE_DIR AS '+DG1/DBNAME/ONLINELOG';
CREATE OR REPLACE DIRECTORY DEST_DIR AS '/..filesystem_path../ONLINELOG';

3-) Copy asm file to filesystem

BEGIN
  dbms_file_transfer.copy_file(source_directory_object =>
  'SOURCE_DIR', source_file_name => 'filename',
  destination_directory_object => 'DEST_DIR',
  destination_file_name => 'filename');
END;
/

4-) Copy file on filesystem back to asm

CREATE OR REPLACE DIRECTORY SOURCE_DIR AS '/..filesystem_path../ONLINELOG';
CREATE OR REPLACE DIRECTORY DEST_DIR AS '+DG2/DBNAME/ONLINELOG';
BEGIN
  dbms_file_transfer.copy_file(source_directory_object =>
  'SOURCE_DIR', source_file_name => 'filename',
  destination_directory_object => 'DEST_DIR',
  destination_file_name => 'new_filename');
END;
/

AIX: ASM Metadata & DISKS

lspv: command used to get disk list (disk, assigned PVID, vg, status)


$lspv
hdisk0          00c2e2503cddd971                    rootvg          active
hdisk9          00c2e2508b71c3a9                    sw_vg           active
hdisk1          none                                None          
hdisk2          none                                None          
hdisk3          none                                None          
...

ASM disks should not have PVID assigned to them (Configuring Storage for Grid Infrastructure, 3.3.3 Configuring Disk Devices for Oracle ASM, step 7). They should be removed with fallowing command before assigned to ASM:

$/usr/sbin/chdev -l hdiskn -a pv=clear

Note: If you already assigned disks without clearing PVID, don't clear it using above command. It corrupts asm disks while clearing header. Because it is the same header where asm keeps its internal info. Actually ASM clears header and PVID and writes its own header when a disk assigned to a datagroup. However because OS odm (aix's internal database) is not updated, you can see PVIDs using lspv although it is not there.

By using following command you can query disk header in order to see ASM internal information written on disk (requires root permission)


$lquerypv -h /dev/rhdisk5
00000000 00820101 00000000 80000000 81AA935B |...............[|
00000010 00000000 00000000 00000000 00000000 |................|
00000020 4F52434C 4449534B 00000000 00000000 |ORCLDISK........|
00000030 00000000 00000000 00000000 00000000 |................|
00000040 0A100000 00000103 54455354 5F303030 |........TEST_000|
00000050 30000000 00000000 00000000 00000000 |0...............|
00000060 00000000 00000000 54455354 00000000 |........TEST....|
00000070 00000000 00000000 00000000 00000000 |................|
00000080 00000000 00000000 54455354 5F303030 |........TEST_000|


In 11g you can backup and recover corrupted disk headers using md_backup and md_restore. The corrupted diskgroup must be specified with the ‘-g’ flag for the restore to complete
successfully:

ASMCMD> md_restore -b /oracle/backup/asm_metadata020409.bkp -g 'TEST'

Ref:
11gRAC_ASM_1.pdf (doc link)

How to Drop ASM Datagroup while not mounted and disks corrupted

In a test environment we accidentally corrupt asm disks and reset their headers. When I query V$ASM_DISK view, I saw that disks were discovered as "CANDIDATE". It was like newly added disks available for ASM. The problem was, my datagroup which was using these disks, was exists but i could not drop it. That was because a diskgroup has to be mounted in order to be dropped, but its disks were corrupted so i could not mount it:

SQL> drop diskgroup DATA;
drop diskgroup DATA
*
ERROR at line 1:
ORA-15039: diskgroup not dropped
ORA-15001: diskgroup "DATA" does not exist or is not mounted


SQL> ALTER DISKGROUP DATA mount;
ALTER DISKGROUP DATA mount
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15017: diskgroup "DATA" cannot be mounted
ORA-15063: ASM discovered an insufficient number of disks for diskgroup "DATA"

How can i drop/delete datagroup which i can not mount?

Solution is to create a new datagroup, add all disks to new datagroup. At the end, old datagroup disappears... Then you may drop newly added diskgroup.

create diskgroup DATA_DROP external redundancy disk '/dev/rhdisk#' force;
alter diskgroup DATA_DROP add disk '/dev/rhdisk#';
...
DATA disappears when i add all its disks to DATA_DROP...
...
drop diskgroup DATA_DROP including contents;

now, DATA diskgroup has gone and all its disks are in "FORMER" status.

How to get process path on linux

$ps -eaf | grep pmon


oracle 24771 1 0 Aug14 ? 00:02:59 ora_pmon_INST1
oracle 28486 1 0 Sep05 ? 00:04:00 ora_pmon_INST2

$readlink -f /proc/24771/exe
/.../bin/oracle
$readlink -f /proc/28486/exe
/.../bin/oracle

SCAN IP Configuration

In order to display scan configuration of RAC cluster:

$srvctl config scan

SCAN name: my-scan.mydomain.com.tr, Network: X/XXX.XXX.XXX.XXX/XXX.XXX.XXX.XXX/en0
SCAN VIP name: scan1, IP: /XXX.XXX.XXX.XXX/XXX.XXX.XXX.XXX
SCAN VIP name: scan2, IP: /XXX.XXX.XXX.XXX/XXX.XXX.XXX.XXX
SCAN VIP name: scan3, IP: /XXX.XXX.XXX.XXX/XXX.XXX.XXX.XXX

AIX: list top 10 processes consume memory

ps aux | head -1; ps aux | sort -rn +5 | head -10

AIX mount-point hdisk information

In order to find relations between mount point and disks follow this procedure:
1-) Find logical volume groups:
lsvg
2-) Find which mount points are belong to which logical volume:
lsvg -l {volume group}
3-) Find which hdisks are belong to logical volume
lslv -l {logical volume}
4-) Finally find storage serial and other information
lscfg -vl {hdisk}