Re: ASM and EMC PowerPath

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.

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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?

>>

>>

>> [...]

>

>

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