Reading ASM Disk Header

How to Read an ASM Disk Header

As root,

/u01/app/11.2.0/grid/bin/kfed read /dev/mapper/mydisk1|egrep "(dsksize|provstr|dskname|grpname|fgname)"

kfdhdb.driver.provstr:  ORCLDISKMYDISK1 ; 0x000: length=15

kfdhdb.dskname:                 MYDISK1 ; 0x028: length=7

kfdhdb.grpname:               MYDISKGROUP ; 0x048: length=9

kfdhdb.fgname:                  MYDISK1 ; 0x068: length=7

kfdhdb.dsksize:                  524294 ; 0x0c4: 0x00080006

To list all ASM devices using blkid:

blkid|grep sd.*oracleasm|while read a b;do echo -n $a$b" scsi_id=";(echo $a|tr -d [:digit:]|tr -d [:]|cut -d"/" -f3|xargs -i scsi_id -g -s /block/{})done;

Rename ASM diskgroup (11.2)

Rename ASM diskgroup

$GRID_HOME/bin/renamedg phase=both verbose=true dgname=OLD_FRA newdgname=NEW_FRA asm_diskstring='ORCL:DISK01','ORCL:DISK02'

Important Note: This does not change the file names/locations in the controlfile. 

1. List all data/temp/control/redo files.

2. Relocate the controlfiles (search this blog for "Multiplexing Controlfiles"). 

3. Rename the diskgroup.

4. Rename datafiles, tempfiles, online/standby redo logfiles using "alter database rename file 'x' to 'y';" with the database in mount mode.