Re: ASM and EMC PowerPath

  • From: "Leyi Zhang (Kamus)" <kamusis@xxxxxxxxx>
  • To: cichomitiko@xxxxxxxxx
  • Date: Sat, 9 Apr 2011 16:20:21 +0800

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@xxxxxxxxx>

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@xxxxxxxxx> 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@xxxxxxxxx>
> 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?
>>
>>
>> [...]
>
>
--
//www.freelists.org/webpage/oracle-l

Other related posts:

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