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

Configure UDEV Rules for Oracle ASM

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Configure UDEV Rules for Oracle ASM

Table of Contents
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Pre-requisites:

a. Create OS user and groups for Oracle ASM disk owner
b. Add RAW disks to server (Check with sysadmin)

Configure UDEV Rules for Oracle ASM:

1. List the disks
2. Create partitions for the disks
3. Load updated block device partition tables
4. Find SCSI ID
5. Create udev rules
6. Reload the udev rules
7. List oracleasm disks

___________________________________________________________________________________________________


Pre-requisites


a. Create OS user and groups for Oracle ASM disk owner

http://www.br8dba.com/create-users-groups-and-paths-for-oracle-rac/


b. Add RAW disks to server





	Operating SystemRed Hat Enterprise Linux release 8.7






	Storage




	/dev/sda100G for Linux and others




	/dev/sdb100G for /u01




	/dev/sdc100G for /orabackup




	/dev/sdd100G for ASM DISK




	/dev/sde100G for ASM DISK


Configure UDEV Rules for Oracle ASM

If ASMLIB kernel drivers are not available then we have to use udev rules to create the disks for Oracle ASM.

Setting up Oracle ASM udev rules is not so complicated. All you need is the udevadm command and editing one file.


1. List the disks

[root@testbox ~]# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda           8:0    0  100G  0 disk
├─sda1        8:1    0    1G  0 part /boot
└─sda2        8:2    0   99G  0 part
  ├─ol-root 252:0    0 61.2G  0 lvm  /
  ├─ol-swap 252:1    0  7.9G  0 lvm  [SWAP]
  └─ol-home 252:2    0 29.9G  0 lvm  /home
sdb           8:16   0  100G  0 disk
└─sdb1        8:17   0  100G  0 part /u01
sdc           8:32   0  100G  0 disk
└─sdc1        8:33   0  100G  0 part /orabackup
sdd           8:48   0  100G  0 disk
sde           8:64   0  100G  0 disk
sr0          11:0    1 47.3M  0 rom
[root@testbox ~]#


2. Create partitions for the disks

fdisk /dev/sdd
fdisk /dev/sde

[root@testbox ~]# fdisk /dev/sdd

Welcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x8c782d71.

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p):

Using default response p.
Partition number (1-4, default 1):
First sector (2048-209715199, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-209715199, default 209715199):

Created a new partition 1 of type 'Linux' and of size 100 GiB.

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

[root@testbox ~]#
[root@testbox ~]# fdisk /dev/sde

Welcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x36462c72.

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p):

Using default response p.
Partition number (1-4, default 1):
First sector (2048-209715199, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-209715199, default 209715199):

Created a new partition 1 of type 'Linux' and of size 100 GiB.

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

[root@testbox ~]#


3. Load updated block device partition tables

# For Linux 5,6 and 7

# /sbin/partprobe /dev/sdd1
# /sbin/partprobe /dev/sde1

# For Linux8

[root@testbox ~]# /sbin/partx -u /dev/sdd1
[root@testbox ~]#
[root@testbox ~]# /sbin/partx -u /dev/sde1
[root@testbox ~]#


4. Find SCSI ID

[root@testbox ~]# /usr/lib/udev/scsi_id -g -u -d /dev/sdd
1ATA_VBOX_HARDDISK_VB0adc00d9-c5938e95
[root@testbox ~]#

[root@testbox ~]# /usr/lib/udev/scsi_id -g -u -d /dev/sde
1ATA_VBOX_HARDDISK_VBdaa5e829-52e4b9b1
[root@testbox ~]#


5. Create udev rules

[root@testbox ~]# ls -ltr /etc/udev/rules.d
total 12
-rw-r--r--. 1 root root  67 Oct  2 18:03 69-vdo-start-by-dev.rules
-rw-r--r--. 1 root root 148 Nov  9 06:11 99-vmware-scsi-timeout.rules
-rw-r--r--. 1 root root 134 Apr  1 07:52 60-vboxadd.rules
[root@testbox ~]#

vi /etc/udev/rules.d/99-oracle-asmdevices.rules
and below lines and then save it.

KERNEL=="sd?1", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d /dev/$parent", RESULT=="1ATA_VBOX_HARDDISK_VB0adc00d9-c5938e95", SYMLINK+="oracleasm/disks/DISK01", OWNER="grid", GROUP="asmadmin", MODE="0660"
KERNEL=="sd?1", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d /dev/$parent", RESULT=="1ATA_VBOX_HARDDISK_VBdaa5e829-52e4b9b1", SYMLINK+="oracleasm/disks/DISK02", OWNER="grid", GROUP="asmadmin", MODE="0660"


[root@testbox ~]# cat /etc/udev/rules.d/99-oracle-asmdevices.rules
KERNEL=="sd?1", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d /dev/$parent", RESULT=="1ATA_VBOX_HARDDISK_VB0adc00d9-c5938e95", SYMLINK+="oracleasm/disks/DISK01", OWNER="grid", GROUP="asmadmin", MODE="0660"
KERNEL=="sd?1", SUBSYSTEM=="block", PROGRAM=="/usr/lib/udev/scsi_id -g -u -d /dev/$parent", RESULT=="1ATA_VBOX_HARDDISK_VBdaa5e829-52e4b9b1", SYMLINK+="oracleasm/disks/DISK02", OWNER="grid", GROUP="asmadmin", MODE="0660"
[root@testbox ~]#

[root@testbox ~]# ls -ltr /etc/udev/rules.d/99-oracle-asmdevices.rules
-rw-r--r--. 1 root root 428 Apr  2 02:18 /etc/udev/rules.d/99-oracle-asmdevices.rules
[root@testbox ~]#


6. Reload the udev rules

The below commands will reload the complete udev configuration and will trigger all the udev rules. 
On a busy production system this could disrupt ongoing operations, applications running on the server. Please use the below command during a scheduled maintenance window only.

[root@testbox ~]# /sbin/udevadm control --reload-rules
[root@testbox ~]#
[root@testbox ~]# ls -ld /dev/sd*1
brw-rw----. 1 root disk 8,  1 Apr  2 02:23 /dev/sda1
brw-rw----. 1 root disk 8, 17 Apr  2 02:23 /dev/sdb1
brw-rw----. 1 root disk 8, 33 Apr  2 02:23 /dev/sdc1
brw-rw----. 1 root disk 8, 49 Apr  2 02:23 /dev/sdd1
brw-rw----. 1 root disk 8, 65 Apr  2 02:23 /dev/sde1
[root@testbox ~]#
[root@testbox ~]# /sbin/udevadm trigger
[root@testbox ~]#
[root@testbox ~]# ls -ld /dev/sd*1
brw-rw----. 1 root disk     8,  1 Apr  2 02:34 /dev/sda1
brw-rw----. 1 root disk     8, 17 Apr  2 02:34 /dev/sdb1
brw-rw----. 1 root disk     8, 33 Apr  2 02:34 /dev/sdc1
brw-rw----. 1 grid asmadmin 8, 49 Apr  2 02:34 /dev/sdd1
brw-rw----. 1 grid asmadmin 8, 65 Apr  2 02:34 /dev/sde1
[root@testbox ~]#


7. List the oracleasm disks

[root@testbox ~]# ls -ltra /dev/oracleasm/disks/*
lrwxrwxrwx. 1 root root 10 Apr  2 02:34 /dev/oracleasm/disks/DISK01 -> ../../sdd1
lrwxrwxrwx. 1 root root 10 Apr  2 02:34 /dev/oracleasm/disks/DISK02 -> ../../sde1
[root@testbox ~]#

[root@testbox ~]# ls -ld /dev/sd*1
brw-rw----. 1 root disk     8,  1 Apr  2 02:34 /dev/sda1
brw-rw----. 1 root disk     8, 17 Apr  2 02:34 /dev/sdb1
brw-rw----. 1 root disk     8, 33 Apr  2 02:34 /dev/sdc1
brw-rw----. 1 grid asmadmin 8, 49 Apr  2 02:34 /dev/sdd1
brw-rw----. 1 grid asmadmin 8, 65 Apr  2 02:34 /dev/sde1
[root@testbox ~]#

Note: symboliclinks are owned by root, but devices will be owned by grid:asmadmin

 

Caution: Your use of any information or materials on this website is entirely at your own risk. It is provided for educational purposes only. It has been tested internally, however, we do not guarantee that it will work for you. Ensure that you run it in your test environment before using.

Thank you,
Rajasekhar Amudala
Email: br8dba@gmail.com
Linkedin: https://www.linkedin.com/in/rajasekhar-amudala/