Two Linux nodes are presented the same storage; but the LUNs are discovered/named differently.

[Shankar Jha]

Hi,
Yes, setup the custom udev rule. So that after reboot, user friendly name
should persist.
On 22-Sep-2011 6:06 AM, "Sanjay Chakraborty" <sanjaychakrab at gmail.com>
wrote:
> Yes you need to setup multipth and give user friendly name. The doc
> you can find in redhat documentation.
>
> On Mon, Sep 19, 2011 at 5:11 PM, Geofrey Rainey
> <Geofrey.Rainey at tvnz.co.nz> wrote:
>> You need to set up multipathing. Oracle Metalink has good documentation
on this, check out note id# 564580.1
>>
>> It has sections such as "A Bit About Udev and Device Name Persistency".
>>
>> Regards,
>> Geofrey Rainey.
>>
>>
>> -----Original Message-----
>> From: redhat-list-bounces at redhat.com [mailto:
redhat-list-bounces at redhat.com] On Behalf Of unix syzadmin
>> Sent: Tuesday, 20 September 2011 2:48 a.m.
>> To: General Red Hat Linux discussion list
>> Subject: Re: Two Linux nodes are presented the same storage; but the LUNs
are discovered/named differently.
>>
>> Hi Matt,
>>
>> Thanks.
>> I am an UNIX admin; not a DBA.
>> >From what I know; DBA plan to use ASM to manage the storage.
>>
>> However; my question is still valid.
>> If two nodes are presented the same storage; why would a EMC LUN  on
node1 be discovered and named differently on node2?
>>
>> node1:
>>
>> emcpowera --> lun# 1346
>>
>> # ls -ld /dev/emcpowera
>> brw-r----- 1 root disk 120, 0 Sep 16 16:17 /dev/emcpowera
>>
>>
>> node2:
>> emcpowerg --> lun#1346
>>
>> # ls -ld /dev/emcpowerg
>> brw-r----- 1 root disk 120, 96 Sep 16 16:23 /dev/emcpowerg
>>
>>
>> >From the above "emcpowera" on node1 is called "emcpowerg" on node2.
>> The LUN number shown in powerpath is same for both of them.
>> Also the minor and major device numbers for the LUNs are different on
both the nodes.
>>
>> It would be better if LUN# 1346 would be discovered as" ecmpowera" on
both the nodes with the same minor/major numbers.
>> I know that most of these are going to be used by ASM and I don't have to
worry.
>>
>> But if there was a problem with LUN#1346; i would have to deal with the
two different device names in both the nodes.
>> This is going to be in production soon and down the line there might be
more storage that might get added.  So for troubleshooting and maintenance I
think it would help if these LUNs were named/discovered similarly on both
the nodes.
>>
>> Thanks,
>>
>>
>>
>> On Mon, Sep 19, 2011 at 9:54 AM, Matty Sarro <msarro at gmail.com> wrote:
>>
>>> You can configure the names used if you want, but you may want to
>>> consider using oracle ASM - then it won't matter what the disks are
>>> named, only what the ASM volume is called. This would only be done on
>>> the first server, and the ASM data should be read by the second server
>>> automatically.
>>> -Matt
>>>
>>> On Mon, Sep 19, 2011 at 9:48 AM, unix syzadmin
>>> <unixsyzadmin at gmail.com>
>>> wrote:
>>> > Hi,
>>> >
>>> > We are setting up 2 RHEL 5.6 server to be used in the oracle RAC
>>> > cluster environment.
>>> >
>>> > We have about 25 X 200G EMC LUNs presented to the servers.
>>> > Since it is the RAC cluster; same LUNs are presented to both the
nodes.
>>> >
>>> > However I see that the names for the LUNs are different on both the
>>> servers.
>>> > for example: "emcpowera"  on node1 is discovered as" emcpowerg" in
node2.
>>> >
>>> >
>>> > Any suggestions/ideas?
>>> > Thanks,
>>> > --
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>
>
>
> --
> Regards.
> Sanjay Chakraborty
>
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