How to find mapping of ASM disks to Physical Devices?

Here I'll show you easy way to find which physical device is corresponding for ASM disk.
Login with root user
1) Identify asm disks

/etc/init.d/oracleasm listdisks
DATA01

2) Query disks FOR DATA01

/etc/init.d/oracleasm querydisk -p DATA01
Disk "DATA01" is a valid ASM disk
/dev/sde2: LABEL="DATA01" TYPE="oracleasm"

or find this way

/etc/init.d/oracleasm querydisk -d DATA01
Disk "DATA01" is a valid ASM disk on device /dev/sde2[8,66]
ls -l /dev | grep 8 | grep 66
brw-r----- 1 root disk     8,  66 Jan 11 06:51 sde2

It means that physical partition sde2 is using for ASM disk DATA01.

Marking disk as an ASM disk FAILED

I ran this command and got the message that the disk does not exist or is not instantiated

/etc/init.d/oracleasm createdisk DISK1 /dev/sdb1
Marking disk "DISK1" as an ASM disk: [FAILED]

I checked for ASM create errors in /var/log/oracleasm and saw this ASM disk error message:

 Disk "DISK1" does not exist or is not instantiated
 Writing disk header: done
 Instantiating disk: oracleasm-instantiate-disk:
 Unable to create ASM disk "DISK1": Permission denied

Solution :
The ASM error - disk does not exist or is not instantiated can be caused by many issues but this is very frequent :
SELINUX isn't disabled.

vi /etc/sysconfig/selinux SELINUX=disabled

Then reboot your system and run getenforce to confirm that SELINUX is disabled:

root> /usr/sbin/getenforce Disable

that's all.

Increase disk size in Oracle Linux on VMware

In this post I'll show you how to extend disk size in oracle linux on vmware.

First of all our vmware guest operating system must be in shutdown mode.
we need to add hard disk to our box.
go to settings--->

click add, then choose hard disk.
check option use an existing virtual disk

then choose file which will expand.

add a new hard disk, go to settings and choose our disk, click utilities--expand and write new size.

power on virtual machine.

our guest system doesn't see a new size

but fdisk shows  the new size

solution :
create new partition on /dev/sda

then,

[root@oel6 ~]# pvcreate /dev/sda3
  Writing physical volume data to disk "/dev/sda3"
  Physical volume "/dev/sda3" successfully created
[root@oel6 ~]# vgextend vg_oel6 /dev/sda3
  Volume group "vg_oel6" successfully extended
[root@oel6 ~]# lvextend -L +18G /dev/vg_oel6/lv_root /dev/sda3  
  Extending logical volume lv_root to 43.60 GiB
  Logical volume lv_root successfully resized
[root@oel6 ~]# resize2fs /dev/mapper/vg_oel6-lv_root 43G
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/vg_oel6-lv_root is mounted on /; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 3
Performing an on-line resize of /dev/mapper/vg_oel6-lv_root to 11272192 (4k) blocks.
The filesystem on /dev/mapper/vg_oel6-lv_root is now 11272192 blocks long.

check size :

it's all, enjoy with new size :)