Re: ASM and EMC PowerPath

From: Radoulov, Dimitre <>
Date: Sun, 10 Apr 2011 11:50:07 +0200
Message-ID: <>

So the first question would be:

what would happen if the path reported by querydisk -d for a given disk is not available?

Would we get an error? Would asm switch to some of the other available paths to the same disk automatically?

If asmlib could handle this, the choice of the path during disk creation should be irrelevant.

Best regards

On 10/04/2011 11:13, Radoulov, Dimitre wrote:
> Hi Leyi,
> answers inline.
>> What my point is , since you can get this result:
>>> # /etc/init.d/oracleasm querydisk -p BLOB
>>> Disk "BLOB" is a valid ASM disk
>>> /dev/sdam1: LABEL="BLOB" TYPE="oracleasm"
>>> /dev/sdbc1: LABEL="BLOB" TYPE="oracleasm"
>>> /dev/emcpowerz1: LABEL="BLOB" TYPE="oracleasm"
>> Then it means emcpower device was used when creatediesk. Actually, no
>> matter what device name was used when createdisk, at least now your
>> "/dev/emcpowerz1" is recognized as ASM Disk BLOB. it's enough (If I'm
>> wrong please correct me).
> Actually, that's what my original email is all about.
> I see that the emcpower devices are recognized as asm disks,
> I don't know if this is enough though ...
> I suppose that querydisk just reports all devices/paths that point
> to the physical disk. What I want to know is if asm is smart
> enough to pick the emcpower device in this case or it
> just uses the first one found (in ASCIIbetical order).
> querydisk -d returns the major/minor of one of the physical paths
> to the disk, not the emcpower path (I checked /proc/partitions for that),
> that's why I think it actually doesn't use the logical devices.
> I say "I think", because I'm not finding this anywhere in the docs for
> now.
>> Query disk typically is safe, you can modify "ORACLEASM_SCANORDER" and
>> "ORACLEASM_SCANEXCLUDE" when you get some downtime in database
>> maintenance window then restart ASM, if disk scanned is not an ASM
>> disk, will just simply raise an error, no data broken. (Of course,
>> backup your database first)
> Thanks for the suggestion!
> Yes, most likely we'll try this first.
>> BTW, can you post /proc/partitions content?
> Yes,
> I'm attaching the content of /proc/partitions.
> Thank you!
> Best regards
> Dimitre

Received on Sun Apr 10 2011 - 04:50:07 CDT

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