Re: ASM and EMC PowerPath

From: Andrew Kerber <andrew.kerber_at_gmail.com>
Date: Sat, 9 Apr 2011 15:01:47 -0500
Message-ID: <BANLkTikEiz28mt33dDy_HPCHDVP2COjYiA_at_mail.gmail.com>



Fyi, it is possible to list specific disks in asm_disktring, eg asm_diskstring='/dev/rdsk/emcpower1','/dev/rdsk/emcpower2','/dev/rdsk/emcpower3'

I think you could add a wildcard on the end of that.

On Sat, Apr 9, 2011 at 2:50 PM, Radoulov, Dimitre <cichomitiko_at_gmail.com>wrote:

>
> Hi Leyi,
> this is an existing live production environment with EMC Powerpath in
> place,
> but ORACLEASM_SCANORDER and ORACLEASM_SCANEXCLUDE are not set.
>
> I know which emcpower devices should be used,
> but I want to know which ones was originally used with the
> createdisk command and which ones are currently in use.
>
> I think that at this point we should:
>
> 1. Find the correct way to add disks to asm, considering the existing
> configuration
> (no ORACLEASM_SCANORDER or/and ORACLEASM_SCANEXCLUDE).
>
> 2. Setup a test environment and try to fix the paths (use the emcpower
> devices,
> instead of the physical ones) there, before doing it in production.
>
>
>
> Best regards
> Dimitre
>
>
>
> On 09/04/2011 10:20, Leyi Zhang (Kamus) wrote:
>
>> 1. For every disk discovered, the first block is reviewed and the
>> ASMLIB label (ORCLDISK<DiskName>) is verified.
>> If found, then the block device<DiskName> is created under the
>> special directory /dev/oracleasm/disks.
>> During the disk discovery, ASMLIB uses file /proc/partitions.
>>
>> 2. If you are using EMC powerpath, you should explicitly set in
>> ORACLEASM_SCANORDER="emcpower" and ORACLEASM_SCANEXCLUDE="sd" in
>> /etc/sysconfig/oracleasm.
>>
>> 3. You can use blkid utility on Linux to determine which disk you used
>> for ASM, the result will tell you clearly which 2 disks are bind into
>> 1 emcpower device, and which emcpower device you can used in ASM to
>> create diskgroups.
>> # blkid | grep asm
>> /dev/sdb1: LABEL="VOL1" TYPE="oracleasm"
>> /dev/sdd1: LABEL="VOL2" TYPE="oracleasm"
>> /dev/sde1: LABEL="VOL3" TYPE="oracleasm"
>> /dev/sdg1: LABEL="VOL4" TYPE="oracleasm"
>> /dev/sdo1: LABEL="VOL1" TYPE="oracleasm"
>> /dev/sdq1: LABEL="VOL2" TYPE="oracleasm"
>> /dev/sdr1: LABEL="VOL3" TYPE="oracleasm"
>> /dev/sdt1: LABEL="VOL4" TYPE="oracleasm"
>> /dev/emcpowerf1: LABEL="VOL4" TYPE="oracleasm"
>> /dev/emcpowerp1: LABEL="VOL3" TYPE="oracleasm"
>> /dev/emcpowero1: LABEL="VOL2" TYPE="oracleasm"
>> /dev/emcpowern1: LABEL="VOL1" TYPE="oracleasm"
>>
>> 4. You can use "oracleasm scandisks" in a live production environment,
>> typically it's safe.
>>
>> 5. There is no need to set "asm_diskstring" manually in most cases.
>>
>> --
>> Kamus<kamusis_at_gmail.com>
>>
>> Visit my blog for more : http://www.dbform.com
>> Join ACOUG: http://www.acoug.org
>>
>>
>>
>> On Sat, Apr 9, 2011 at 2:47 PM, Radoulov, Dimitre<cichomitiko_at_gmail.com>
>> wrote:
>>
>>> Hi Andrew,
>>> thanks! I didn't know about kfod, I'll check it's output on Monday (kfod
>>> disk=all -> path).
>>>
>>> I don't have an access to the systems right now, but if I recall
>>> correctly,
>>> v$asm_disk.path shows as ORCL:<disk_name>
>>> (so most probably asm_diskstring is set to ORCL:* or similar, I'll check
>>> that on Monday too).
>>>
>>>
>>>
>>> Thank you!
>>>
>>> Dimitre
>>>
>>>
>>>
>>> On 08/04/2011 22:22, Andrew Kerber wrote:
>>>
>>> I believe there are options with kfod to do some of this. The
>>> asm_diskstring parameter should show you how it is finding the disks
>>> currently. As I recall, if you try and change asm_diskstring, and
>>> current
>>> disks arent listed it wont let you.
>>>
>>> On Fri, Apr 8, 2011 at 4:04 AM, Radoulov, Dimitre<cichomitiko_at_gmail.com>
>>> wrote:
>>>
>>>> One more question:
>>>>
>>>> - oracleasm querydisk -p shows correctly all paths (physical and
>>>> logical)
>>>> to the devices.
>>>> - oracleasm querydisk -d shows the first one found during discovery
>>>>
>>>> How can we know which path was used originally, when the disk was
>>>> created?
>>>>
>>>>
>>>> [...]
>>>>
>>>
>>>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

-- 
Andrew W. Kerber

'If at first you dont succeed, dont take up skydiving.'

--
http://www.freelists.org/webpage/oracle-l
Received on Sat Apr 09 2011 - 15:01:47 CDT

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