How To Setup ASM & ASMLIB On Native Linux Multipath Mapper disks

How To Setup ASM & ASMLIB On Native Linux Multipath Mapper disks

After installed and configured the Multipath, follow bellow:

1. Download and Install ASMLIB :
http://www.oracle.com/technetwork/topics/linux/asmlib/index-101839.html

 We installed proper oracleasm rpms

2. Check the disks :

[root@linux01 ~]#ls -l /dev/mapper

brw-rw---- 1 root disk 253, 46 Jul 27 17:19 Mpatha01

brw-rw---- 1 root disk 253, 67 Jul 27 17:59 Mpatha02

brw-rw---- 1 root disk 253, 36 Jul 27 17:19 Mpatha03

brw-rw---- 1 root disk 253, 58 Jul 27 18:00 Mpatha04

 Note: above disks are partitioned from Luns.

3. Create the ASMLIB disks on mapper partitions as follow:

[root@linux01 ~]# /etc/init.d/oracleasm createdisk DSKORA1  /dev/mapper/Mpatha01

[root@linux01 ~]# /etc/init.d/oracleasm createdisk DSKORA2  /dev/mapper/Mpatha02

After create the disks, the ASM put a mark on the disks to know which are your own.

 4. If this is a RAC configuration, then from each node execute:

[root@linux01 ~]# /etc/init.d/oracleasm scandisks

[root@linux01 ~]# /etc/init.d/oracleasm listdisks

5. Configure ASMLIB to use multipath  (from each node on RAC environments):

[root@linux01 grid]# /usr/sbin/oracleasm configure

ORACLEASM_ENABLED=true

ORACLEASM_UID=grid

ORACLEASM_GID=asmadmin

ORACLEASM_SCANBOOT=true

ORACLEASM_SCANORDER=" "

ORACLEASM_SCANEXCLUDE=" "

ORACLEASM_USE_LOGICAL_BLOCK_SIZE="false"

Note:  Now we have to update above two bold character parameters else ASM diskgroup creation or next ASM startup will not work properly for Disk Group.

Option1:

Modify in /etc/sysconfig/oracleasm :
ORACLEASM_SCANORDER=”dm”
ORACLEASM_SCANEXCLUDE=”sd”

Restart ASMLIB (from each node on RAC environments):
/etc/init.d/oracleasm stop
/etc/init.d/oracleasm start

Option2:

[root@linux01 grid]# /usr/sbin/oracleasm configure -i -e -u grid -g asmadmin -o "dm"  -x "sd"

[root@linux01 grid]# /usr/sbin/oracleasm exit

[root@linux01 grid]# /usr/sbin/oracleasm init

[root@linux01 grid]# /usr/sbin/oracleasm scandisks

[root@linux01 grid]# /usr/sbin/oracleasm configure

ORACLEASM_ENABLED=true

ORACLEASM_UID=grid

ORACLEASM_GID=asmadmin

ORACLEASM_SCANBOOT=true

ORACLEASM_SCANORDER="dm"

ORACLEASM_SCANEXCLUDE="sd"

ORACLEASM_USE_LOGICAL_BLOCK_SIZE="false"

6. Verify if the configuration is correct:

6.1 During the disk discovery, ASMLIB uses file /proc/partitions, see :

[root@linux01 grid]#  cat /proc/partitions

   8     0  877264896 sda

   8     1     104391 sda1

   8     2  877157032 sda2

   8    16  209715200 sdb

   8    32  382730240 sdc

   8    48  379596800 sdd

   8    64    2097152 sde

   8    80    2097152 sdf

   8    96 1169776640 sdg

 253     6  209715200 dm-6

 253     7  382730240 dm-7

 253     8  379596800 dm-8

 253     9    2097152 dm-9

 253    10    2097152 dm-10

6.2 The ASMLIB mount disks at /dev/oracleasm/disks, see:

# ls -la /dev/oracleasm/disks

brw-rw---- 1 grid asmadmin 253,  6 Ago 16 16:33 DSKORA1

brw-rw---- 1 grid asmadmin 253,  7 Ago 16 16:33 DSKORA2

6.3 Check if major and minor of disks “dm” not “sd”, is the same in /proc/partitions  and /dev/oracleasm/disks , see “253″ and “6″ bellow:

[root@linux01 grid]# cat /proc/partitions

253     6  209715200 dm-6

[root@linux01 grid]# ll /dev/oracleasm/disks

brw-rw---- 1 grid asmadmin 253,  6 Ago 16 16:33 DSKORA1

You can check using querydisk too :

[root@linux01 grid]#  /etc/init.d/oracleasm querydisk -d DSKORA1

Disk "DSKORA1" is valid ASM disk on device [253, 6]