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PowerPath and Oracle ASM in a RAC Environment
Hello all, a customer asked a question about Power Path and Oracle ASM in a RAC environment. They would like to know how we support PP in the RAC environment with ASM if the pseudo device names do not match across the cluster. As you can see in the example below the devices are different across the cluster;
I am looking for any guidance on supporting RAC with PowerPath and any whitepapers that explain how to set things up.
Here is a list of the disks. Let me know if this helps:
DEVRAC01:
emcpowero [mtlwhsdevrac_voting_211]
emcpowern [mtlwhsdevrac_voting_212]
emcpowerp [mtlwhsdevrac_voting_213]
emcpowerb [mtlwhsdevrac_redo_207]
emcpowera [mtlwhsdevrac_redo_209]
emcpowerk [mtlwhsdevrac_archive_208]
emcpowerj [mtlwhsdevrac_data_197]
emcpowerl [mtlwhsdevrac_data_198]
emcpowerh [mtlwhsdevrac_data_199]
emcpoweri [mtlwhsdevrac_data_200]
emcpowerm [mtlwhsdevrac_data_201]
emcpowere [mtlwhsdevrac_data_202]
emcpowerg [mtlwhsdevrac_data_203]
emcpowerd [mtlwhsdevrac_data_204]
emcpowerc [mtlwhsdevrac_data_205]
emcpowerf [mtlwhsdevrac_data_206]
DEVRAC02:
emcpowern [mtlwhsdevrac_voting_211]
emcpowero [mtlwhsdevrac_voting_212]
emcpowerp [mtlwhsdevrac_voting_213]
emcpoweri [mtlwhsdevrac_redo_207]
emcpowerb [mtlwhsdevrac_redo_209]
emcpowerl [mtlwhsdevrac_archive_208]
emcpowerj [mtlwhsdevrac_data_197]
emcpowerf [mtlwhsdevrac_data_198]
emcpowerm [mtlwhsdevrac_data_199]
emcpowere [mtlwhsdevrac_data_200]
emcpowerh [mtlwhsdevrac_data_201]
emcpowerk [mtlwhsdevrac_data_202]
emcpowerc [mtlwhsdevrac_data_203]
emcpowera [mtlwhsdevrac_data_204]
emcpowerg [mtlwhsdevrac_data_205]
emcpowerd [mtlwhsdevrac_data_206]
Thank you.
Nick
we have many RAC where emcpowerX devices do not match, while my system admins/DBA prefer for them to match ..they tend to get renamed after PowerPath or kernel upgrades. PowerPath has utilities that allow you either manually rename devices or export devices list from one node and import it on another.
Please find the below white paper ‘Using Oracel DB ASM with EMC Storage’. Although it is a bit old in 2005, it does address the issue you raised.
http://www.oracle.com/technetwork/database/asm-on-emc-5-3-134797.pdfIn the section ‘RAC and powerpath (page 19), there may be cased where the path names are not consistent across nodes of a cluster, this is not an issue for ASM, since ASM does not require that the disks have same disk be visible to each ASM instance via that instances’ discovery string. Using PowerPath command powermt display dev=all, to find the common Logical Device (logical ids). The two paths (from two different nodes) will reference the same physical Sym device if they have the same PowerPath logical id.
MacBookPro_9_2
46 Posts
1808
0
Posted December 30th, 2012 07:00
And if you are using Solutions Enabler, you can also use the syminq utility to grep for the device serial numbers and verify that they match across all RAC nodes
NickPOW1
2 Intern
•
94 Posts
1808
0
Posted December 27th, 2012 06:00
Thank you all for your coments. We'll use the PowerPath emcpadm utility to match the emcpower names.
Nick