Would like to know if this is correct disk configuration for 11.2.0.3

Question

Hello, please see the procedure below that I used to allow the grid infratstructure 11.2.0.3 oui to be able
to recognize mY EMC San disks as candidate disks for use with ASM.
we are using EMC powerpath for our multipathing as stated in the original problem description.I want to know if this is a fully supported method for
configuring our san disks for use with oracle ASM becuase this is redhat 6 and we do not have the option to use the asmlib driver.Please note that I have
been able to successfully install the gird infrastructure successfully for a 2 node RAC cluster at this point using this method.Please let me know if there
any issue with configuring disks using this method.
We have the following EMC devices which have been created in the /dev directory.I will be using device emcpowerd1 as my disk for the ASM diskgroup I will be
creating for the ocr and voting device during grid install.
[root@qlndlnxraccl01 grid]# cd /dev
[root@qlndlnxraccl01 dev]# ls -l emc*
crw-r--r--. 1 root root 10, 56 Aug 1 18:18 emcpower
brw-rw----. 1 root disk 120, 0 Aug 1 19:48 emcpowera
brw-rw----. 1 root disk 120, 1 Aug 1 18:18 emcpowera1
brw-rw----. 1 root disk 120, 16 Aug 1 19:48 emcpowerb
brw-rw----. 1 root disk 120, 17 Aug 1 18:18 emcpowerb1
brw-rw----. 1 root disk 120, 32 Aug 1 19:48 emcpowerc
brw-rw----. 1 root disk 120, 33 Aug 1 18:18 emcpowerc1
brw-rw----. 1 root disk 120, 48 Aug 1 19:48 emcpowerd
brw-rw----. 1 root disk 120, 49 Aug 1 18:54 emcpowerd1
brw-rw----. 1 root disk 120, 64 Aug 1 19:48 emcpowere
brw-rw----. 1 root disk 120, 65 Aug 1 18:18 emcpowere1
brw-rw----. 1 root disk 120, 80 Aug 1 19:48 emcpowerf
brw-rw----. 1 root disk 120, 81 Aug 1 18:18 emcpowerf1
brw-rw----. 1 root disk 120, 96 Aug 1 19:48 emcpowerg
brw-rw----. 1 root disk 120, 97 Aug 1 18:18 emcpowerg1
brw-rw----. 1 root disk 120, 112 Aug 1 19:48 emcpowerh
brw-rw----. 1 root disk 120, 113 Aug 1 18:18 emcpowerh1
As you can see the permissions by default are root:disk and this will be set at boot time.These permissions do not allow the Grid Infrastructure to recognize
the devices as candidates for use with ASM so I have to add udev rules to assign new names and permissions during boot time.
Step 1. Use the scsi_id command to get the unique scsi id for the device as follows.
[root@qlndlnxraccl01 dev]# scsi_id whitelisted replace-whitespace --device=/dev/emcpowerd1
360000970000192604642533030434143
Step 2. Create the file /etc/udev/rules.d/99-oracle-asmdevices.rules
Step 3. With the scsi_id that was obtained for the device in step 1 you need to create a new rule for that device in the /etc/udev/rules.d/99-oracle-
asmdevices.rules file. Here is what the rule for that one device looks like.
KERNEL=="sd*1" SUBSYSTEM=="block",PROGRAM="/sbin/scsi_id --whitelisted --replace-whitespace /dev/$name",RESULT=="360000970000192604642533030434143",NAME="asm
crsd1",OWNER="grid",GROUP="asmadmin",MODE="0660"
( you will need to create a new rule for each device that you plan to use as a candidate disk for use with oracle ASM).
Step 4. Reboot the host for the new udev rule to take affect and then verify that the new device entry will be added into the /dev directory with the
specified name, ownership and permissions that are required for use with ASM once the host is back online.
Note: You will need to replicate/copy the /etc/udev/rules.d/99-oracle-asmdevices.rules file to all nodes in the cluster and restart them for the changes to
be in place so that all nodes can see the new udev device name in the /dev directory on each respective node.
You should now see the following device on the host.
[root@qlndlnxraccl01 rules.d]# cd /dev
[root@qlndlnxraccl01 dev]# ls -l asm*
brw-rw----. 1 grid asmadmin 65, 241 Aug 2 10:10 asmcrsd1
Step 5. Now when you are running the oui installer for the grid installation when you get to the step where you define your ASM diskgroup you should choose
external redundancy and then click on the change disk dicovery path and change the disk discovery path as follows.
/dev/asm*
Now at this point you will see the new disk name asmcrsd1 showing as a condidate disk for use wiith ASM.
PLease let us know if this is a supported method for our shared disk configuration.
Thank you.

Answer 1

Hi,
I've seen this solution in a lot of forums but I do not agree or don't like at all; even if we have 100 luns of 73GB each.
so the thing is, as in any other unix flavor we don't have asmlib***just EMCPOWERPATH running on differentes unix/linux flavors we dont like either udev-rules, dm-path and stuff***
Try this as root user
ls -ltr emcpowerad1
brw-r----- 1 root disk 120, 465 Jul 27 11:26 emcpowerad1
# mknod /dev/asmdisks
# chown oragrid:asmadmin /dev/asmdisks
# cd /dev/asmdisks
# mknod VOL1 c 120 465
# chmod 660 /dev/asmdisks/VOL*
repeat above steps on second node
asm_diskstring='/dev/asmdisks/*'
talk with sysadmin and stoadm guys to garanty naming and persistents in all nodes of your RAC using emcpowerpath. (even after reboot or san migration)