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How to Use Udev Rules to Create oracleasm Disks in CentOS/RHEL 8

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This post will help to configure Oracleasm disks using Udev rules in 2 node cluster.

On first node

1. List the disks:

[root@node01 ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda  8:0     0  2G   0       disk
sdb  8:16    0  2G   0       disk
Note: Create partitions for the disks.

2. Find the disk ID:

[root@node01 ~]# udevadm info --query=all --name=/dev/sda | egrep "WWN|SERIAL"
E: ID_SCSI_SERIAL=[id]
E: ID_SERIAL=0QEMU_QEMU_HARDDISK_AAAAAAAAA
E: ID_SERIAL_SHORT=[id]
E: SCSI_IDENT_SERIAL=[id]
[root@node01 ~]# udevadm info --query=all --name=/dev/sdb | egrep "WWN|SERIAL"
E: ID_SCSI_SERIAL=[id]
E: ID_SERIAL=0QEMU_QEMU_HARDDISK_BBBBBBBBB
E: ID_SERIAL_SHORT=[id]
E: SCSI_IDENT_SERIAL=[id]

3. Create a new file 96-asm.rules:

[root@node01 ~]# touch /etc/udev/rules.d/96-asm.rules

4. Append the file 96-asm.rules with discovered information of disk ID:

[root@node01 ~]# vim /etc/udev/rules.d/96-asm.rules
## Disk /dev/sda
KERNEL=="sd*", SUBSYSTEM=="block", ENV{ID_SERIAL}=="0QEMU_QEMU_HARDDISK_AAAAAAAAA", SYMLINK+="oracleasm/DATA1", OWNER="oracle", GROUP="dba", MODE="0660"
## Disk /dev/sdb
KERNEL=="sd*", SUBSYSTEM=="block", ENV{ID_SERIAL}=="0QEMU_QEMU_HARDDISK_BBBBBBBBB", SYMLINK+="oracleasm/DATA2", OWNER="oracle", GROUP="dba", MODE="0660"

5. Reload the udev/rules:

[root@node01 ~]# udevadm control --reload-rules
[root@node01 ~]# udevadm trigger --type=devices --action=change

6. List the oracleasm disk:

[root@node01 ~]# ll /dev/oracleasm/DATA*
lrwxrwxrwx. 1 root root 6 Sep 28 14:24 /dev/oracleasm/DATA1 -> ../sda
lrwxrwxrwx. 1 root root 6 Sep 28 14:24 /dev/oracleasm/DATA2 -> ../sdb
[root@node01 ~]#

On Second Node

1. List the disks:

[root@node02 ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda  8:0     0  2G   0       disk
sdb  8:16    0  2G   0       disk
Note: /dev/sd* devices name will not persistence after reboot, find with disk id.

2. Find the disk ID:

[root@node02 ~]# udevadm info --query=all --name=/dev/sdb | egrep "WWN|SERIAL"
E: ID_SCSI_SERIAL=[id]
E: ID_SERIAL=0QEMU_QEMU_HARDDISK_AAAAAAAAA
E: ID_SERIAL_SHORT=[id]
E: SCSI_IDENT_SERIAL=[id]
[root@node02 ~]# udevadm info --query=all --name=/dev/sdc | egrep "WWN|SERIAL"
E: ID_SCSI_SERIAL=[id]
E: ID_SERIAL=0QEMU_QEMU_HARDDISK_BBBBBBBBB
E: ID_SERIAL_SHORT=[id]
E: SCSI_IDENT_SERIAL=[id]

3. Create a new file 96-asm.rules:

[root@node02 ~]# touch /etc/udev/rules.d/96-asm.rules

4. Either copy the 96-asm.rules from other node or make a new entry with discovered information:

[root@node02 ~]# vim /etc/udev/rules.d/96-asm.rules
## Disk /dev/sdb
KERNEL=="sd*", SUBSYSTEM=="block", ENV{ID_SERIAL}=="0QEMU_QEMU_HARDDISK_AAAAAAAAA", SYMLINK+="oracleasm/DATA1", OWNER="oracle", GROUP="dba", MODE="0660"
## Disk /dev/sdc
KERNEL=="sd*", SUBSYSTEM=="block", ENV{ID_SERIAL}=="0QEMU_QEMU_HARDDISK_BBBBBBBBB", SYMLINK+="oracleasm/DATA2", OWNER="oracle", GROUP="dba", MODE="0660"

5. Reload the udev/rules:

[root@node02 ~]# udevadm control --reload-rules
[root@node02 ~]# udevadm trigger --type=devices --action=change

6. List the oracleasm disk:

[root@node02 ~]# ll /dev/oracleasm/DATA*
lrwxrwxrwx. 1 root root 6 Sep 28 14:57 /dev/oracleasm/DATA1 -> ../sdb
lrwxrwxrwx. 1 root root 6 Sep 28 14:57 /dev/oracleasm/DATA2 -> ../sdc
[root@node02 ~]#
Note: For multipath device use the device name accordingly.

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