How to Delete GRID

Method 1:

export GRID_HOME=/oracle/app/oracle/product/12.2.0.1/grid
cd $GRID_HOME/deinstall
./deinstall

Method 2:

1) Remove GRID home
backup inventory.xml

cp /oracle/app/oraInventory/ContentsXML/inventory.xml /oracle/app/oraInventory/ContentsXML/inventory.xml.20210205

option1:This not work???

export ORACLE_HOME=/oracle/app/oracle/product/12.2.0.1/grid
ORACLE_HOME/oui/bin/runInstaller -detachHome -silent -local ORACLE_HOME=ORACLE_HOME
verify:
cat /oracle/app/oraInventory/ContentsXML/inventory.xml

option2: edit the file

vi /oracle/app/oraInventory/ContentsXML/inventory.xml

delete the line “12.2.0.1”

2)
comment out +ASM in /etc/oratab

3)delete /etc/oracle

mv /etc/oracle /etc/oracle.20210225

4) recreate disk group CRS
record what are the CRS disk? These will be used to recreate disk group.

if you don’t know the disk info:

oracleasm querydisk -d CRS
Disk "CRS" is a valid ASM disk on device [8,49]

ls -l sd*
brw-rw---- 1 root disk 8,  0 Feb 25 19:28 sda
brw-rw---- 1 root disk 8,  1 Feb 25 19:28 sda1
brw-rw---- 1 root disk 8,  2 Feb 25 19:28 sda2
brw-rw---- 1 root disk 8, 16 Feb 25 21:57 sdb
brw-rw---- 1 root disk 8, 17 Feb 25 21:57 sdb1
brw-rw---- 1 root disk 8, 32 Feb 25 21:57 sdc
brw-rw---- 1 root disk 8, 33 Feb 25 21:57 sdc1
brw-rw---- 1 root disk 8, 48 Feb 25 21:57 sdd
brw-rw---- 1 root disk 8, 49 Feb 25 21:57 sdd1

sudo fdisk -l |grep sdd
Disk /dev/sdd: 5368 MB, 5368709120 bytes, 10485760 sectors
/dev/sdd1            2048    10485759     5241856   83  Linux

sdd1(8,49) is the disk.

sudo oracleasm deletedisk CRS
cd /dev/
ls -l sd*
brw-rw---- 1 root disk 8,  0 Feb 25 19:28 sda
brw-rw---- 1 root disk 8,  1 Feb 25 19:28 sda1
brw-rw---- 1 root disk 8,  2 Feb 25 19:28 sda2
brw-rw---- 1 root disk 8, 16 Feb 25 21:53 sdb
brw-rw---- 1 root disk 8, 17 Feb 25 21:53 sdb1
brw-rw---- 1 root disk 8, 32 Feb 25 21:53 sdc
brw-rw---- 1 root disk 8, 33 Feb 25 21:53 sdc1
brw-rw---- 1 root disk 8, 48 Feb 25 21:53 sdd
brw-rw---- 1 root disk 8, 49 Feb 25 21:53 sdd1

sudo oracleasm createdisk CRS sdd1

磁盘设备中的major和minor device number:
在linux和unix下所有的一切都是文件，major device number可以看作是设备的驱动程序，那么被同一设备驱动程序管理的设备当然具备相同的majob device number，这个值实际也是kernel中的device driver table的索引。

而minor device number是被访问的具体设备，kernel先根据major device number找到设别的驱动程序，然后从minor device number获取设备的具体属性。

例如：裸设备的驱动程序major device number是162

[oracle@asm1:/dev/raw]ll
total 0
crw-rw---- 1 root disk 162, 0 Feb 25 19:28 rawctl