Re: ASM and EMC PowerPath

  • From: "Radoulov, Dimitre" <cichomitiko@xxxxxxxxx>
  • To: Karl Arao <karlarao@xxxxxxxxx>
  • Date: Sun, 10 Apr 2011 14:31:44 +0200


Hi Karl,
thanks for the information (and thanks for adding partprobe to the list).
The report you mention reports DBSO1DATA1 with major/minor 8, 33 (ls -l /dev/oracleasm/disks). This is the device sdc1 and emcpowerp is the logical path (the EMC Power path) to that device (if I understanding it right). But emcpowerp has different major/minor numbers, so I would expect to see its major/minor numbers, 
if the disk is accessed through the emcpower path.

Of course, I could be totally wrong.


Could you please check if on the RAC you produced the report on,
ORACLEASM_SCANORDER or ORACLEASM_SCANEXCLUDE are set in /etc/sysconfig/oracleasm? 



Thanks
Dimitre

On 10/04/2011 12:33, Karl Arao wrote:


Hi Dimitre,

See my answers below:

1) Question: which path should we use with the createdisk command?
Answer: You should use the /dev/emcpowerz1 , note that as per the official doc you need to specify the whole disk partition
2) Question: Is the multipathing used , given querydisk -d returns the major/minor numbers of the phisical device? Answer: Kindly check on this wiki to know the mapping of ASM to EMC Power Devices http://karlarao.tiddlyspot.com/index.html#ASMtoEMCPowerDevices This will show you a storage report that maps the relationship from the Oracle layer (ASM), Linux, and SAN storage. This info is very useful for you and the storage engineer. So you would know which is which in case of catastrophic problems..
3) Question: After adding and marking the disks for asm from one node, we'll need to run oracleasm scandisks on the remaining nodes, is it safe to run this command (scandisks) in a live production environment? 
Answer:
- First you have to make a whole disk partition on that shared EMC Power Device on the 1st node, after doing that you have to issue "partprobe" (as root) on the remaining nodes - Second, you'll execute the "createdisk" on the 1st node... after that, you have to issue "oracleasm scandisks" on the remaining nodes - Third, you should verify on all the nodes by executing "oracleasm listdisks"
Is it safe to do this? mmm.. I would allocate a window for doing this activity just to be safe.. or do it first on test environment or R&D machines.. 




--
Karl Arao
karlarao.wordpress.com <http://karlarao.wordpress.com>
karlarao.tiddlyspot.com <http://karlarao.tiddlyspot.com>

Other related posts:

  1. Home
  2. oracle-l
  3. Archive
  4. 04-2011